Kostyuk vs Samsonova — Marta Kostyuk

Kalshi — primary rule

If Marta Kostyuk wins the Kostyuk vs Samsonova professional tennis match in the 2026 WTA Guadalajara Quarterfinal after a ball has been played, then the market resolves to Yes.

Polymarket — resolution criteria

This market refers to the tennis match between Marta Kostyuk and Liudmila Samsonova in the Guadalajara Open Akron, originally scheduled for September 17, 2026 at 12:00PM ET. This market will resolve to 'Marta Kostyuk' if Marta Kostyuk advances against Liudmila Samsonova. This market will resolve to 'Liudmila Samsonova' if Liudmila Samsonova 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 October 1, 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.