Analysis of 9,698 ATP matches: 42.35% go to a deciding set; when they do, the first set winner wins 57% of the time. Grand Slam vs ATP Tour splits and implications for set betting and live betting.

The decisive set: third set and fifth set statistics that matter for bettors

Published: February 2026
Reading Time: 11 minutes
Category: Tennis Statistics & Probability

Introduction

When a match goes to a deciding set—the third set in best-of-three or the fifth set in best-of-five—momentum, fatigue, and nerves all play a role. But what does the data actually say? How often do matches go the distance? And when they do, does the player who won the first set usually close it out, or do comebacks dominate?

We analyzed 9,698 ATP matches from 2022–2025 (with full set-by-set scores) from our tournament database to answer these questions. Every number in this article comes from that dataset—no estimates, no industry averages from elsewhere.

Bottom line: In our sample, 42.35% of matches went to a deciding set. When they did, the player who won the first set went on to win the match 57% of the time. So the “first set winner” has an edge in deciding sets, but it’s far from a lock—which has clear implications for set betting and live betting.

How often do matches go to a deciding set?

Across 9,698 matches with parseable scores:

Straight sets (2-0 or 3-0): 5,591 matches (57.65%)
Deciding set (2-1, 3-1, or 3-2): 4,107 matches (42.35%)

So in well over two in five matches, the outcome is decided in the final set. That’s a lot of high-leverage moments—and a lot of opportunity for set markets and in-play betting.

Set count distribution Figure 1: Distribution of match length by number of sets played (9,698 ATP matches, 2022–2025).

Breakdown by set count:

2 sets: 4,905 (50.6%) — best-of-three finished in straight sets
3 sets: 3,684 (38.0%) — best-of-three went to a deciding third set
4 sets: 686 (7.1%) — best-of-five finished in four sets
5 sets: 423 (4.4%) — best-of-five went to a deciding fifth set

So in best-of-three, about 43% of matches that don’t end in straight sets go to a third set; in best-of-five, a similar idea applies for the fifth set. That’s the “deciding set” we care about for the rest of the article.

When the match goes to a deciding set, who usually wins?

We looked at all 4,107 matches that went to a deciding set (third or fifth) and asked: did the player who won the first set also win the match?

Result:

First set winner won the match: 2,341 times (57.0%)
First set loser came back to win: 1,766 times (43.0%)

So the first-set winner has a real but modest edge: about a 57–43 split. That’s useful for thinking about “first set winner → match winner” in deciding-set matches, and it lines up with the kind of edge we see in first set correlation with match outcome—strong, but not a guarantee.

First set winner vs match winner when deciding set Figure 2: When the match goes to a deciding set, the first set winner wins 57% of the time (2,341 vs 1,766).

Takeaway for bettors: If you’re betting on the match winner after the first set in a deciding-set situation, the first-set winner is the better pick on average—but the underdog wins 43% of the time, so odds and value still matter more than the raw 57% number.

Grand Slam vs ATP Tour: more deciding sets at the majors

We split the sample into Grand Slam (best-of-five) and ATP Tour (mostly best-of-three) to see if the pattern changed.

Grand Slam (502 matches with score):

65.74% of matches went to a deciding set (third, fourth, or fifth set that decided the match)
When they did, the first set winner won 69.09% of the time

ATP Tour (9,196 matches):

41.07% went to a deciding (third) set
When they did, the first set winner won 55.94% of the time

So at the Slams, both (a) the share of matches that go the distance and (b) the first-set winner’s win rate in those matches are higher. That fits the idea that best-of-five rewards the better player more often and that the “first set winner” at Slams is often the stronger player who then closes in four or five. For more on how majors differ from regular events, see our Grand Slam betting guide.

Deciding set rate and first set winner win rate by tournament type Figure 3: Grand Slam matches go to a deciding set more often, and the first set winner wins those deciding-set matches more often (69% vs 56%).

Set count distribution: two, three, four, and five sets

The next chart summarizes how match length is distributed across the same 9,698 matches. Most ATP matches are best-of-three, so the bulk are 2-set or 3-set; the 4-set and 5-set bars are from Grand Slams and a few other best-of-five events.

Set count distribution bar chart Figure 4: Number of matches ending in 2, 3, 4, or 5 sets (9,698 matches).

Rates (from our data):

2 sets: 50.6%
3 sets: 38.0%
4 sets: 7.1%
5 sets: 4.4%

So about 9.5% of all matches in the sample went to four or five sets (i.e. best-of-five), and the rest were best-of-three. That’s useful for pricing “match length” or “number of sets” markets if you’re building or checking models.

Why the deciding set matters for betting

Three practical implications:

1. Set betting and “over/under sets”

With 42.35% of matches going to a deciding set, “over 2.5 sets” (in best-of-three) or “over 5.5 sets” (in best-of-five) hits more often than casual intuition might suggest.
If the book’s line doesn’t reflect a ~42% chance of a deciding set in best-of-three, there may be value in the over.

2. Live betting after the first set

When the match is 1–0 in sets, the first-set winner goes on to win 57% of the time overall and 69% at Slams in our sample.
So after set one, the first-set winner is a statistical favorite—but the underdog still wins 43% (tour) and 31% (Slams). Pricing and value still matter; don’t blindly back the first-set winner at short odds unless the number is right.

3. Fatigue and fifth sets

Fifth sets are rare (4.4% of all matches) but highly visible. They’re also more common at Slams, where the first-set winner closes the match at a 69% rate when it goes the distance.
If you’re building a model or a mental framework for Slams, treating “first set winner in a deciding-set match” as a strong but not certain signal is consistent with this 69% figure.

For more on using first-set and set-level data in your strategy, see First set wins: the most undervalued betting market? and our analysis of 10,000 tennis matches.

Summary: key numbers to remember

9,698 ATP matches with full set-by-set scores (2022–2025).
42.35% of matches went to a deciding set (third or fifth).
When they did, the first set winner won 57.0% of the time (2,341 vs 1,766).
Grand Slam: 65.74% of matches went to a deciding set; first set winner won 69.09% of those.
ATP Tour: 41.07% went to a deciding set; first set winner won 55.94% of those.
Set distribution: 2 sets 50.6%, 3 sets 38.0%, 4 sets 7.1%, 5 sets 4.4%.

The decisive set is where a large share of matches are actually decided—and where the first-set winner has a real but not overwhelming edge. Use that when you think about set markets, live betting, and building a view on match length and comeback likelihood.

Summary infographic decisive set Figure 5: Summary of decisive-set and first-set-winner stats (9,698 matches).

Data: 9,698 ATP matches with parseable set-by-set scores from our tournament cache (2022–2025). All percentages are from this dataset.