A double fault costs a fantasy tennis player points twice: once on the scoring line, where many formats deduct for it, and again on the scoreboard, where it hands the opponent a free point. The first cost is small. The second is what swings close matches, and it is why double-fault tendencies belong in your pre-match research next to aces, break points and surface.
TL;DR
- A double fault happens when both serves miss, and the point goes to the returner, per the ITF tennis glossary.
- The biggest daily fantasy operators deduct 1 point per double fault in both best-of-three and best-of-five scoring, according to FTN Fantasy's DFS tennis primer.
- The same analysts warn that heavy double-faulters hurt both the floor and the ceiling of a lineup, and that a winner with 10 or more double faults can still score less than the loser in a tight match.
- Treat double faults as a rate and a context question: serve style, surface, opponent return quality and pressure moments matter more than one night's count.
- Use them as a tiebreaker between two similar picks, not as your first filter.
Table of Contents
- What a double fault is and why it counts
- How double faults hit your fantasy score directly
- The indirect cost: free points, breaks and bad games
- Raw counts mislead: use rates and context
- How to read double faults next to other stats
- Surface, conditions and pressure
- A simple double-fault checklist for lineup day
- A worked example
- Where the stats come from
- Our perspective
- Put it to work in a real tournament
- FAQ
- Sources
What a double fault is and why it counts
The rule is simple. The server gets two attempts to land a serve in the correct box. If both miss, it is a double fault and the returner wins the point. The ITF glossary defines it exactly that way, and every professional scoring feed records it as a standalone stat.
That clean definition hides two different events. One is the forced double fault, where a player swings hard on a second serve because a break point is staring at them. The other is the unforced drift, where rhythm, toss or nerves simply leave. In the box score they look identical. In your fantasy lineup they are not the same signal, and learning to tell them apart is where the analytical edge lives.
How double faults hit your fantasy score directly
Most fantasy tennis formats score a match as a sum of small events: games won, sets won, aces, breaks, and a match-win bonus. Negative events subtract from that total. Double faults are the standard negative serve event.
Per FTN Fantasy's breakdown, both DraftKings-style and FanDuel-style scoring deduct points for double faults, and DraftKings takes off 1 point per double fault regardless of match length. Rules differ by game and can change, so always read the scoring page of the format you are entering before you set a lineup. In Tweener, check the scoring details for each mode inside the app before a tournament starts.
What does 1 point per double fault mean in practice? It depends on how much a single ace or game is worth in that format, but the shape of the problem is consistent:
| Player type | Typical profile | Direct fantasy effect |
|---|---|---|
| Big server, high risk | Many aces, many double faults | Aces and double faults partly cancel out; variance is high |
| Safe server | Fewer aces, few double faults | Low variance; points come from games won and break chances |
| Weak second serve | Double faults plus short second-serve points | Direct deductions plus opponent break chances |
| Strong returner facing weak server | Opponent hands over free points | Indirect boost to the returner's break count |
The direct cost is rarely what loses you a week. The indirect cost is.
The indirect cost: free points, breaks and bad games
A double fault is a free point, and free points arrive at the worst time. A server who double faults at 30-40 has handed over a break chance without the opponent striking a ball. That break costs the server a game, may cost a set, and can decide who wins the match, which in most formats carries the largest single bonus.
The FTN Fantasy analysts put the stakes plainly: players who double fault at a high rate can significantly hurt both the ceiling and the floor of a lineup's points. They give a concrete picture too: a player with 10 or more double faults may finish with fewer fantasy points than the opponent despite winning a close best-of-three match. That is the key insight. A double-fault problem can erase the very result you rostered the player for.
Think about it in three layers:
- Point level. One free point for the opponent.
- Game level. Double faults cluster. One often leads to a tense next serve, then another.
- Match level. Lost service games push matches to extra sets, which sometimes raises raw volume of stats but also raises the chance of an upset against your pick.
When you scan a slate, ask which layer is more likely to matter for each player.
Raw counts mislead: use rates and context
A tempting shortcut is to look at last week's double-fault total and avoid anyone with a high number. That is a poor method for two reasons.
Match length distorts counts. A five-set slog gives a player more service games, so more chances to miss. A player who double faults 9 times in five sets is not necessarily worse than one who double faults 5 times in a straight-sets win. Compare double faults per service game or as a share of total serves, not just totals. Our guide to what tennis player stats mean walks through the rate stats worth saving in your notes.
Style drives the baseline. Players who attack the second serve with pace and spin or who hit a flat, risky second ball will always show more double faults than players who steer it in. Some of that is the price of a big serve, and the aces on the other side of the ledger can make up for it. A server with a high double-fault count and a high ace count may be a fine pick; a server with a high double-fault count, few aces and a soft second serve is the player to fade.
That is also why serve speed alone is a weak predictor. We cover the balance in our five-step guide to serve speed and aces.
How to read double faults next to other stats
A double-fault number means little in isolation. Pair it with these.
First-serve percentage
A player who lands fewer first serves hits more second serves, which means more double-fault chances. If a player's first-serve percentage drops during a tournament while the double-fault count rises, that is a form signal, not noise. If only the count rises, it may just be a long match.
Second-serve points won
This is the companion stat. A player can double fault a lot and still win a decent share of second-serve points because the rally serves are strong. Another can rarely double fault yet win few second-serve points because the ball sits up for the returner. The first player is riskier on the scoring line; the second is riskier on the scoreboard.
Aces
Aces are the positive side of the same serve. If you are comparing two servers, look at the aces-minus-double-faults gap. A wide positive gap suggests a serve that produces more than it gives away. A narrow or negative gap is a warning, especially on slower courts where the return gets more time.
Break points faced and saved
Double faults on break points are the ones that hurt. A player who faces many break points and saves few is the player whose double faults tend to turn into lost games. Our rundown of WTA stats every fantasy gamer should know covers serve and return numbers that matter on the women's tour, where breaks of serve are more frequent and a shaky service game costs more.
Opponent return quality
A double-faulter facing a passive returner can survive. The same player facing an elite returner who attacks second serves will see every weakness punished. Always grade the double-fault risk against who is standing on the other side of the net.
Surface, conditions and pressure
Surface changes how serves land and how costly a miss is. On faster courts, a good first serve earns cheap points, so a player with a shaky second serve can hide it by landing more firsts. On slower courts, the returner gets more time to attack, so a second serve that merely lands is not safe. Wind, heat and altitude change toss and ball flight too, which is why outdoor Slams can produce wild serving days that indoor events rarely do.
Pressure matters as well. Early rounds against a weaker opponent tend to be low-stress service days. Late rounds, tiebreaks and deciding sets raise the stakes for everyone. If your pick has a history of tightening up in big moments, a double-fault spike late in a match can flip a game that looked secure. Our piece on why tracking player performance matters in fantasy tennis covers building a simple form log so you can spot trends like these before the draw is final.
A simple double-fault checklist for lineup day
Before you lock a lineup, run each serve-heavy pick through five quick questions:
- Is the double-fault rate high relative to the player's own service games, not just the last match?
- Does the player offset it with a strong ace total or strong first-serve percentage?
- What is the surface, and does it reward or punish a weak second serve?
- How good is the opponent's return, and do they attack second serves?
- Is the match best-of-three or best-of-five? Longer matches create more serve volume and more variance.
If a player fails two or more, look for an alternative at a similar price or similar draw position. If two players are otherwise equal, take the cleaner server. That is the tiebreaker use of double faults, and it is the one that holds up best over a season.
A worked example
Imagine two hypothetical players in the same round, both favorites.
- Player A hits hard and goes for the lines. In a typical match, A sends down plenty of aces and also gives away a handful of double faults. The two roughly cancel out on the scoring line.
- Player B serves with moderate pace, rarely double faults, but wins a lower share of second-serve points.
On raw double-fault count, B looks safer. But if A's opponent is a mediocre returner, A's serve can dominate, and the aces outweigh the deductions. If B's opponent is an aggressive returner, B's soft second serve will be punished by breaks, not by a scoring penalty. The right pick depends on the matchup, not on the headline count. This is the kind of reasoning that rewards analytical fans, and it is nothing like picking a name off a ranking list. For a framework that goes beyond one stat, see how to choose tennis players for fantasy leagues.
Where the stats come from
Before you rely on any stat, know how it is recorded. Double faults are logged point by point by official scoring systems, and small differences in how services and fault calls are handled can show up in the data. We explain the pipeline in how sports statistics are collected for fantasy tennis, and it is worth a read if you plan to build your own spreadsheet.
Our perspective
Fantasy tennis is a skill game because the sport is so granular. Every point is an event, every serve is data, and the double fault is a small stat that tells you a lot about how a player is handling a match. Most casual fans never look at it, which is exactly why it is useful to you.
We built Tweener around tennis alone because tennis does not behave like other sports. There is no team to smooth out a bad day. One player, one racquet, one serve. When someone's second serve breaks down, you see it at once in the score and in your lineup. That is what makes preparation pay off, and why we think analytical fans deserve a game made for them rather than a tennis tab bolted onto something else.
Our advice is to treat double faults as context, not a veto. Pair them with first-serve percentage, second-serve points won, surface and opponent return strength, then decide. In private leagues with up to 9 friends for a Grand Slam, small edges like that are what separate first place from the middle of the table.
Nathan
Put it to work in a real tournament
The best way to learn how double faults behave is to track them across a full event. Tweener lets you build fantasy teams from real ATP and WTA players, play in Draft Mode or Pick'em Mode, and score on actual match results. You can start in free play with virtual coins, or play paid contests where legally permitted. Cash contests are available only in select US states, so check eligibility when you sign up. Explore the modes at Tweener or download the app.
If you want to practice the research habits in this article, our fantasy tennis prediction games guide and the fantasy tennis terms glossary are good next stops.
FAQ
Do double faults really cost fantasy points?
Yes, in the major daily fantasy formats. FTN Fantasy reports that DraftKings deducts 1 point per double fault in both best-of-three and best-of-five scoring. Other games set their own values, so read the scoring page before you enter.
Is a high double-fault count always a reason to avoid a player?
No. A big server may double fault often and still make up for it with aces and quick holds. Look at the rate per service game, the ace count and second-serve points won. Avoid the player whose double faults come with few aces and a weak second serve.
Can a player win a match and still score poorly in fantasy?
Yes. The same analysts note that a player with 10 or more double faults may score fewer points than the opponent even after winning a close best-of-three match. Deductions plus a thin margin of games can outweigh the win bonus in some formats.
Which matters more, the double-fault count or the matchup?
The matchup usually matters more. A shaky second serve is far costlier against an aggressive returner, on a slower court or in a late-round pressure spot. Use the count as one input and rank the matchup context above it.