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Predictions graded

Naomi Osaka #13Japan2Elise Mertens #23Belgium1

Sets 6-3 · 3-6 · 7-5Sat 5 Sept 2026, 23:04 Predictions gradedThird RoundHard

Predictions3–3–250%

Edges2–3–240%

Player Profiles

Ranking advantageNaomi Osaka · 10 places

Naomi Osaka

Japan

Former world No. 1 and four-time major champion, with all four major titles won on hard courts. She returned from maternity leave in 2024 and reached the 2025 Montreal final and US Open semifinal.

Current ranking: #13
Peak ranking: #1 · 2019
Current age: 28
Preferred surface: Hard
Hand: Right handed
Height: 180 cm

Elise Mertens

Belgium

Reached a career-high No. 12 on 26 November 2018. Her major singles results include the 2018 Australian Open semifinal and the 2026 Wimbledon quarterfinal.

Current ranking: #23
Peak ranking: #12 · 2018
Current age: 30
Preferred surface: Hard
Hand: Right handed
Height: 179 cm

Quick Take

Pre-match view

Context last updated 3 Sep 2026, 22:28 · Europe/Bucharest

Osaka's dominant 2026 H2H (straight-set wins) and superior hard-court serve/return metrics make her a strong favorite.

Best bets: Osaka moneyline (edge 4.5pts) and under 21.5 total games (edge 7.4pts). Avoid Mertens +4.5 games as Osaka covers easily.

Context

Osaka, 28, is a former US Open champion and currently ranked No. 13. Mertens, 30, is ranked No. 20 and has been a consistent top-30 player.
Osaka's recent dominance in this matchup is striking: she won 6-1 6-2 on hard in August and 6-3 6-3 on grass in June. Those wins suggest she has a clear tactical edge, but Mertens has won three of their nine career meetings, so the pattern is not absolute.
- Osaka won 6-1 6-2 on hard court on 2026-08-07.
- Osaka won 6-3 6-3 on grass on 2026-06-23.
- Osaka leads the overall head-to-head 6-3.
Osaka's hard-court record this season is 12-5, and she has won 77.8% of her last nine hard matches. Mertens is 16-9 on hard in 2026.
Osaka's recent hard-court numbers are better across the board: she wins 53.7% of total points versus Mertens' 50.6%, and she converts break points at 47.3% compared to Mertens' 40.3%. Mertens has been competitive but less efficient, which could matter in a tight third-round match.
- Osaka's last 9 hard-court matches: 7-2 record, 53.7% total points won.
- Mertens' last 9 hard-court matches: 6-3 record, 50.6% total points won.
- Osaka's break point conversion on hard: 47.3%; Mertens': 40.3%.
Osaka, 28, is the WTA No. 13 and right-handed. She withdrew from Cincinnati on 12 August citing fatigue after seven matches across Washington and Toronto.
The skipped Cincinnati event reduced her late-swing match workload before New York. That rest could help her freshness, but it also means she enters the US Open without a tune-up event.
- The withdrawal was explicitly for fatigue.
- Her Washington and Toronto run comprised seven matches, including two three-setters.
- Stored recent sample: 4 wins from 5 tracked matches.
ConfirmedSources checked 3 Sep 2026, 22:26 · Europe/BucharestWTA Officialwww.wtatennis.com · 12 Aug 2026
Mertens has played several three-set matches in her recent run, including a 2-6 6-2 6-2 loss to Diane Parry and a 1-6 6-4 6-2 win over Nikola Bartunkova.
Mertens' longer average match duration could mean she is used to grinding, but it also raises the risk of fatigue in a Grand Slam third round. Osaka's shorter matches may leave her fresher, though she has also had some tough battles.
- Mertens' last 15 matches average 111.4 minutes; Osaka's average 86.6 minutes.
- Mertens has played 5 three-set matches in her last 15; Osaka has played 4.

BetBugs edges

Compare BetBugs' chances with the market's.

Positive edges · 6

BetBugs probabilities

How likely BetBugs thought each outcome was.

Result1 of 1 landed

Signal quality High · Uncertainty band Strong lean · Market price 1.36
The read
Osaka's dominant 2026 H2H wins and stronger hard-court serve/return profile give her a clear edge.
- Osaka leads H2H 6-3 overall and 4-3 on hard, including 6-1 6-2 and 6-3 6-3 wins in 2026.
- Osaka's last 15 hard-court record is 7-2 (77.8%), with 57.3% games won.
- Mertens' last 15 hard-court record is 6-3 (66.7%), with 53.0% games won.
- Osaka's last-15 overall return points won is 41.9% vs Mertens' 42.5%, but Osaka's first-serve points won is 73.6% vs Mertens' 70.1%.
BetBugs · Match WinnerwonNaomi OsakaEstimated chance78%

Games0 of 1 landed

Signal quality Medium · Uncertainty band Lean · Market price 1.83
The read
Osaka's straight-set dominance in recent H2H suggests a relatively short match.
- Osaka's last-15 hard-court matches average 95.8 minutes and 57.3% games won.
- Mertens' last-15 hard-court matches average 120.7 minutes and 53.0% games won.
- 2026 H2H matches had 15 and 12 total games, both under 21.5.
BetBugs · Total GameslostUnder 21.5Estimated chance62%
Signal quality Medium · Uncertainty band Lean · Market price 1.80
The read
Osaka's early breaks in recent H2H first sets point to a quick opener.
- Osaka won the first set 6-1 and 6-3 in 2026 H2H matches.
- Osaka's last-15 hard-court first-serve points won is 72.8%.
- Mertens' last-15 hard-court first-serve points won is 70.7%.
BetBugs · Set 1 Total GamespushUnder 9.5Estimated chance60%
Signal quality Medium · Uncertainty band Lean · Market price 1.80
The read
Osaka's ability to break Mertens' weaker second serve should keep the second set short.
- Osaka won the second set 6-2 and 6-3 in 2026 H2H matches.
- Mertens' last-15 hard-court second-serve points won is only 45.3%.
- Osaka's last-15 hard-court break-point conversion is 47.3%.
BetBugs · Set 2 Total GamespushUnder 9.5Estimated chance58%

Sets1 of 3 landed

Signal quality Medium · Uncertainty band Strong lean · Market price 1.44
The read
Osaka's strong first-set record and recent H2H dominance support her taking the opener.
- Osaka won the first set in both 2026 H2H matches (6-1, 6-3).
- Osaka's career first-set win conversion is 90%, while Mertens' is 87%.
- Osaka's last-15 hard-court first-serve points won is 72.8% vs Mertens' 70.7%.
BetBugs · Set 1 WinnerwonNaomi OsakaEstimated chance72%
Signal quality Medium · Uncertainty band Strong lean · Market price 1.50
The read
Osaka's straight-set H2H wins and superior hard-court set percentage make a two-set match likely.
- Osaka won both 2026 H2H matches in straight sets.
- Osaka's last-15 hard-court record is 7-2 with 71.4% sets won.
- Mertens' last-15 hard-court record is 6-3 with 60.9% sets won.
BetBugs · Total SetslostUnder 2.5Estimated chance70%
Signal quality Medium · Uncertainty band Strong lean · Market price 1.40
The read
Osaka's superior second-serve and break-point efficiency on hard courts should carry the second set.
- Osaka won the second set in both 2026 H2H matches (6-2, 6-3).
- Osaka's last-15 hard-court second-serve points won is 55.4% vs Mertens' 45.3%.
- Mertens' last-15 hard-court break-point conversion is 40.3% vs Osaka's 47.3%.
BetBugs · Set 2 WinnerlostNaomi OsakaEstimated chance68%

Match stats1 of 1 landed

Signal quality Medium · Uncertainty band Strong lean · Not priced
The read
Osaka's straight-set wins without tiebreaks in recent H2H make a tiebreak unlikely.
- Neither 2026 H2H match featured a tiebreak.
- Osaka's last-15 hard-court matches show a 57.3% games won rate, suggesting comfortable sets.
- Mertens' last-15 hard-court matches show a 53.0% games won rate.
BetBugs · Tiebreak in MatchwonNoEstimated chance65%
Signal quality Low · Uncertainty band Slight lean · Not priced
The read
Both players' ace rates suggest a combined total above 9.5, though variance is high.
- Osaka averages 7.0 aces per match on hard courts in last 15.
- Mertens averages 5.5 aces per match on hard courts in last 15.
- Combined average is 12.5 aces per match.
BetBugs · Total Acesnot gradableOver 9.5Estimated chance55%
Signal quality Low · Uncertainty band Slight lean · Not priced
The read
Mertens' high double-fault rate and Osaka's moderate rate push the combined total above 7.5.
- Osaka averages 3.4 double faults per match on hard courts in last 15.
- Mertens averages 5.5 double faults per match on hard courts in last 15.
- Combined average is 8.9 double faults per match.
BetBugs · Total Double Faultsnot gradableOver 7.5Estimated chance52%

Prediction history

Naomi Osaka has been highly reliable when projected to win

Naomi Osaka has fulfilled 14 of 15 recent win predictions, a 93% fulfilment rate. Her average estimated probability was 66.5%, yet she won 14 matches, exceeding the expected 10. The only miss came against Karolina Muchova at 58% probability, while her successful predictions averaged 67.1%.

Recent evidence for Naomi Osaka15 matches

Date / competitionMatch resultPredictedActualResult

31 Jul·WTA Washington

#71Elisabetta Cocciaretto1-2#13Naomi Osaka

BetBugsNaomi Osaka to win·72%

Matched

31 Jul 2026

WTA Washington

#71Elisabetta Cocciaretto1-2#13Naomi Osaka

Naomi Osaka to win

72%probability

Naomi Osaka won

Matched

30 Jul·WTA Washington

#67Ashlyn Krueger0-2#13Naomi Osaka

BetBugsNaomi Osaka to win·62%

Matched

30 Jul 2026

WTA Washington

#67Ashlyn Krueger0-2#13Naomi Osaka

Naomi Osaka to win

62%probability

Naomi Osaka won

Matched

3 Jul·WTA Wimbledon

#65Daria Kasatkina0-2#14Naomi Osaka

BetBugsNaomi Osaka to win·62%

Matched

3 Jul 2026

WTA Wimbledon

#65Daria Kasatkina0-2#14Naomi Osaka

Naomi Osaka to win

62%probability

Naomi Osaka won

Matched

1 Jul·WTA Wimbledon

#225Anastasia Gasanova0-2#14Naomi Osaka

BetBugsNaomi Osaka to win·85%

Matched

1 Jul 2026

WTA Wimbledon

#225Anastasia Gasanova0-2#14Naomi Osaka

Naomi Osaka to win

85%probability

Naomi Osaka won

Matched

29 Jun·WTA Wimbledon

#82Elsa Jacquemot0-2#15Naomi Osaka

BetBugsNaomi Osaka to win·78%

Matched

29 Jun 2026

WTA Wimbledon

#82Elsa Jacquemot0-2#15Naomi Osaka

Naomi Osaka to win

78%probability

Naomi Osaka won

Matched

Head-to-Head

6-3 (9 meetings)

W6-1 6-2Naomi Osaka#13vElise Mertens#20Aug 7, 2026

W6-3 6-3Naomi Osaka#13vElise Mertens#20Jun 23, 2026

L6-3 6-4Naomi Osaka#13vElise Mertens#20Aug 8, 2024

W6-2 6-4Naomi Osaka#13vElise Mertens#20Jun 11, 2024

L7-5 6-4Naomi Osaka#13vElise Mertens#20Mar 11, 2024

W6-3 6-3Naomi Osaka#13vElise Mertens#20Mar 29, 2021

W6-2 7-6(5)Naomi Osaka#13vElise Mertens#20Aug 28, 2020

W6-4 6-1Naomi Osaka#13vElise Mertens#20Sep 21, 2019

L6-4 1-6 6-4Naomi Osaka#13vElise Mertens#20Sep 25, 2017

9 total meetings

Previous match context available

Naomi Osaka

11W 4L

6-2 5-7 6-1#42Katerina Siniakova

7-6(6) 7-6#101Anastasia Zakharova

4-6 7-6(5) 6-4#2Elena Rybakina

6-4 6-4#33Leylah Annie Fernandez

6-1 6-2#20Elise Mertens

6-2 6-4#68Panna Udvardy

6-4 6-2#18Alexandra Eala

4-6 6-4 6-3#67Elisabetta Cocciaretto

6-3 3-1 ret.#60Ashlyn Krueger

7-6(4) 6-4#7Karolina Muchova

6-2 7-6(2)#1Aryna Sabalenka

6-1 6-3#61Daria Kasatkina

6-3 6-2#192Anastasia Gasanova

6-1 7-5#114Elsa Jacquemot

6-1 1-0 ret.#7Karolina Muchova

Elise Mertens

10W 5L

6-2 7-6(5)#86Maria Timofeeva

6-4 6-4#107Kaitlin Quevedo 6-4 0-6 6-3#31Diane Parry 1-6 6-4 6-2#34Nikola Bartunkova 6-1 6-4#58Yuliia Starodubtseva

6-1 4-6 6-3#68Panna Udvardy

2-6 6-2 6-2#31Diane Parry

6-1 6-2#13Naomi Osaka

3-6 6-4 6-4#73Anna Bondar

6-3 7-5#6Linda Noskova

6-4 6-4#26Marie Bouzkova

7-6(4) 6-1#2Elena Rybakina

2-6 6-3 6-0#86Maria Timofeeva

6-2 6-4#102Laura Siegemund

6-3 6-3#13Naomi Osaka

Stat Battle

Last 15 match performance, compared side by side.

NONaomi OsakaOsaka

Last 15

6–1

9 core stats · 2 even

Elise MertensMertensEM

Naomi Osaka carries the stronger recent form — Elise Mertens's route runs through pressure.

Serve · 4–0 · 1 even

1st Serve In14/15 · 14/1557.1%—56.7%

1st Serve Won14/15 · 14/1573.6%+3.5pp70.1%

2nd Serve Won14/15 · 14/1553.7%+9.7pp44.0%

Aces / Match14/15 · 14/156.9+2.04.9

Double Faults / Match14/15 · 14/152.63.0 fewer5.6

Return · 0–0 · 1 even

Return Pts Won14/15 · 14/1541.9%—42.5%

Pressure · 1–1

Break Pts Converted14/15 · 14/1547.2%+1.3pp45.9%

Break Pts Saved14/15 · 14/1560.9%+1.3pp62.2%

Points · 1–0

Total Pts Won14/15 · 14/1553.5%+2.8pp50.7%

Shot making · 2–0 · 1 evenLimited data · 6 vs 6

Winners / Match6/15 · 6/1525.7+6.918.8

Unforced Errors / Match6/15 · 6/1522.3—22.2

Net Pts Won6/15 · 6/1567.3%+2.1pp65.2%

Serve · 4–0 · 1 even

57.1%1st Serve In14/15 · 14/15—56.7%

73.6%1st Serve Won14/15 · 14/15+3.5pp70.1%

53.7%2nd Serve Won14/15 · 14/15+9.7pp44.0%

6.9Aces / Match14/15 · 14/15+2.04.9

2.6Double Faults / Match14/15 · 14/153.0 fewer5.6

Return · 0–0 · 1 even

41.9%Return Pts Won14/15 · 14/15—42.5%

Pressure · 1–1

47.2%Break Pts Converted14/15 · 14/15+1.3pp45.9%

60.9%Break Pts Saved14/15 · 14/15+1.3pp62.2%

Points · 1–0

53.5%Total Pts Won14/15 · 14/15+2.8pp50.7%

Shot making · 2–0 · 1 evenLimited data · 6 vs 6

25.7Winners6/15 · 6/15+6.918.8

22.3Unforced Errors6/15 · 6/15—22.2

67.3%Net Pts Won6/15 · 6/15+2.1pp65.2%

Naomi Osaka

Elise Mertens

Quick Take

Context

BetBugs edges

Naomi Osaka

Naomi Osaka

Under 2.5

Under 21.5

Under 9.5

Under 9.5

Naomi Osaka

Result1 of 1 landed

Games0 of 1 landed

Sets1 of 3 landed

Match stats1 of 1 landed

Head-to-Head

Naomi Osaka

Elise Mertens

Stat Battle