3 Best US Open Bets and Predictions for Day 4

The final Grand Slam of the year, the US Open, is underway this week.

We should see plenty of fun matches and storylines emerge in the coming days, and FanDuel Sportsbook has US Open odds for all the matches over the next two weeks.

Let's see which second-round matches could have the most betting value on Wednesday.

US Open Betting Picks for Day 4

Frances Tiafoe vs. Martin Damm

Tiafoe 3-0 Sets (-120)

Frances Tiafoe regularly saves his best for the US Open, reaching the semifinals in 2024 and 2022 and the quarterfinals in 2023. Another deep run can't be ruled out, and if nothing else, Martin Damm isn't likely to be the one who gives him trouble.

The 21-year-old Damm is ranked 431st and made it into the main draw as a qualifier, having spent the entire season playing in Challenger and ITF tournaments. This is his first time playing in the main draw of a Grand Slam, and it's just his fifth career ATP-level match.

Damm didn't drop a set in three qualifying matches, and he won his first-round encounter versus Darwin Blanch in straight sets, as well. However, all four of those opponents were ranked 200th or worse, so taking on the world No. 17 is a major step up in competition.

In fact, this will be just Damm's second match ever versus a top-20 opponent. The only other time was at 2024 Miami, where he was down a set to Tommy Paul before Paul badly rolled his ankle and was forced to retire.

Needless to say, Tiafoe holds a significant edge in experience.

At 6'8", Damm does possess a potent serve -- he racked up 24 aces in his win over Blanch -- and showed potential as a junior, so we shouldn't be surprised if Tiafoe finds himself in some tight sets. However, with Damm's lack of matches versus high-level competition, we should ultimately see Tiafoe prevail in straight sets.

Tennis Abstract views Tiafoe as a massive favorite, giving him a 97.5% win probability.

Jan-Lennard Struff vs. Holger Rune

Rune -4.5 Games (-124)

Holger Rune suffered a first-round exit at Wimbledon due in part to a knee issue, but he's coming off a solid summer on hard courts, advancing to the round of 16 at the Canadian Open and the quarterfinals in Cincinnati. This is one of his best surfaces, as he's won 67% of his hard-court matches over the last 52 weeks and ranks 11th in Tennis Abstract's Elo ratings on hard courts.

Jan-Lennard Struff is having a forgettable campaign, going 9-18 overall and 3-8 on hard courts entering the tournament. He lost two straight hard-court matches before coming to New York (a qualifier and Challenger), which didn't even count toward his ATP record.

Given all that, the 35-year-old looked to be an unlikely candidate to make it through US Open qualifying, but he snuck his way through and then survived a four-set encounter with world No. 100 Mackenzie McDonald in the first round to reach today's match.

With questionable form and a hard court Elo rating outside the top 100, Struff shouldn't give Rune much trouble. Tennis Abstract forecasts an 87.3% win probability for Rune, and this isn't a huge spread for him to cover. Rune also has +170 odds to win in straight sets, which is another intriguing option.

Ben Shelton vs. Pablo Carreno Busta

Under 32.5 Total Match Games (-116)

Ben Shelton's tendency to find himself in tiebreaks is a slight concern for this one, but with his odds to win in straight sets shortening to -135, this under is shaking out as the better value. Shelton cruised through his first-rounder in 27 games (6-3, 6-2, 6-4), and we're hoping for a similar result versus Pable Carreno Busta.

Carreno Busta was a solid player at his peak, but he's ranked outside the top 100, and his best days seem to be behind him at age 34. The Spaniard entered the US Open with a 6-11 overall record in 2025 and 4-6 on this surface. He failed to make any noise in any of his three warm-up tournaments on hard courts, and a first-round victory over world No. 361 Pablo Llamas Ruiz doesn't exactly move the needle, either.

On the other hand, Shelton's play is on an upward trajectory after winning the Canadian Open, and his rising stock is backed by having the fourth-shortest odds to win the tournament (+2000). His also 6th in hard court Elo rating, whereas Carreno Busta is 66th.

Tennis Abstract is showing an 87.3% win chance for Shelton. He ought to be able to get another straight-sets win, and if he can avoid tiebreakers, he should be able to keep this below 33 games.

You can also check out our 2025 US Open men's bracket and women's bracket, both available as free printable downloads at FanDuel Research.

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The above author is a FanDuel employee and is not eligible to compete in public daily fantasy contests or place sports betting wagers on FanDuel. The advice provided by the author does not necessarily represent the views of FanDuel. Taking the author’s advice will not guarantee a successful outcome. You should use your own judgment when participating in daily fantasy contests or placing sports wagers.