Best Bets & Predictions for Osaka vs Mertens

• Naomi Osaka is a sound -334 favorite vs Elise Mertens in Round 3 women’s singles action at the US Open
• Osaka won their most recent documented meeting at Bad Homburg in 2026 without dropping a set
• See my Osaka vs Mertens best bets and predictions, along with updated odds below

Naomi Osaka will try to book her ticket into Round 4 in women’s singles at the US Open, as she takes on Elise Mertens on Saturday.

Osaka enters as the heavy chalk (getting -334 odds to win outright), boasting overwhelming power on hard courts. Mertens, meanwhile, assumes the familiar role of a gritty underdog trying to neutralize an elite baseline attack.

Osaka vs Mertens is scheduled for Saturday, September 5 at the USTA Billie Jean King National Tennis Center in Flushing Meadows, New York — though the time and court have yet to be determined.

American viewers will be able to catch the action on ESPN, while viewers in Canada can tune in on TSN.

Osaka vs Mertens Best Bets and Predictions

• Pick: Osaka to Win 2-0 (-117 at Kalshi)

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Exact-Score Prediction

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Kalshi

Osaka Wins 2-0 Sets

54%

Predict

Osaka’s power gives her the clearest route to controlling short rallies, while Mertens must extend points and create pressure on return.

Backing the hefty chalk on the moneyline offers no value, but grabbing Osaka to win 2-0 at -117 is a highly wagerable angle. Still, this is not a matchup in which Osaka has been unbeatable: Mertens owns two hard-court wins in the listed 2024 meetings. Osaka needs to reproduce the serve-plus-first-strike tennis that produced her latest straight-set victory.

• Pick: Under 21.5 Total Games (-122 at Kalshi)

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O/U Prediction

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Kalshi

Under 21.5 Games

55%

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The under is supported by Osaka’s 6-3, 6-3 win in the latest meeting, which totaled 18 games. Several other meetings also ended in straight sets, giving Osaka a path to cashing this total if she protects her serve and avoids prolonged sets.

However, the full history is more mixed than the previous version of this handicap suggested. Mertens has taken Osaka to competitive sets and has beaten her twice on hard courts, so the under is best framed as a secondary play rather than an automatic result. I am locking in the Under 21.5 games at -122, with the expectation that Osaka’s power can keep the match below the number.

Given Mertens’ inability to extend sets against Osaka’s massive serve, this match will conclude quickly and hit the under. Across their two 2026 matchups, neither contest featured an elongated, competitive set. Their Bad Homburg meeting concluded at a tidy 18 games, while the Toronto matchup was an absolute rout, ending in just 15 games.

Mertens has struggled mightily to find break points, generating just four total opportunities across those two matches and converting only one. Because Mertens cannot sustain rallies or reliably break the Osaka serve, she simply cannot push sets to six or seven games. I am locking in the Under 21.5 games at -122 as a sturdy secondary play.

Osaka vs Mertens Odds

Odds as of Sept 4 at bet365. Get a bet365 bonus code to wager on all tennis matches.

Mertens has struggled mightily to find break points, generating just four total opportunities across those two matches and converting only one. Because Mertens cannot sustain rallies or reliably break the Osaka serve, she simply cannot push sets to six or seven games.