- Set 2 Winner: Kostyuk vs Stephens81¢
- Kostyuk vs. Stephens: Set 1 Games O/U 8.558¢
- Kostyuk vs. Stephens: Set 2 Games O/U 9.550¢
- Set Handicap: Kostyuk (-1.5) vs Stephens (+1.5)66¢
- Kostyuk vs. Stephens: Set 1 Games O/U 9.550¢
- Kostyuk vs. Stephens: Set 1 Games O/U 10.520¢
- Kostyuk vs. Stephens: Set 2 Games O/U 10.550¢
- Game Spread: Kostyuk (-5.5) vs Stephens (+5.5)53¢
- Kostyuk vs. Stephens: Match O/U 22.537¢
- US Open WTA: Marta Kostyuk vs Sloane Stephens87¢
- US Open WTA: Completed Match: Marta Kostyuk vs Sloane Stephens50¢
- Kostyuk vs. Stephens: Match O/U 21.539¢
This market refers to the tennis match between Marta Kostyuk and Sloane Stephens in the US Open WTA, originally scheduled for September 2, 2026 at 11:00AM ET. This market will resolve to 'Marta Kostyuk' if Marta Kostyuk advances against Sloane Stephens. This market will resolve to 'Sloane Stephens' if Sloane Stephens advances against Marta Kostyuk. If the match is canceled (not played at all), ends in a tie, or a winner has not been determined by September 16, 2026, 11:59 PM ET (14 days after the scheduled start), this market will resolve to 50-50. If the match begins but is not completed, and one player advances due to the opponent's retirement, default, or disqualification, this market will resolve to the player who advances. If the match ends in a walkover (player withdraws before the start and the other advances automatically), this market will resolve to 50-50. The primary resolution source will be official information from the WTA Tour. A consensus of credible reporting may also be used.
Marta Kostyuk enters this US Open second-round matchup as the clear form player, ranked No. 11 with a 32-8 record in 2026 after semifinals at the French Open and Wimbledon plus strong hard-court results in Toronto and Cincinnati. The Ukrainian defeated Sloane Stephens 7-5, 7-5 in their recent Cincinnati encounter and has shown consistent depth on outdoor hard courts. Stephens, the 2017 champion and a wild card ranked outside the top 200, snapped a long Grand Slam win drought with a straight-sets first-round victory over Clara Tauson and draws motivation from home crowds plus recent ranking gains. The American’s experience on these courts and ability to raise her level in New York provide realistic upset potential against the higher-seeded favorite.