TORONTO — After winning just one game on serve in the first set, Iga Świątek rallied to defeat Marta Kostyuk 3-6, 6-1, 6-2 to advance to the Canadian Open quarterfinals Saturday afternoon.This marks the six-time Slam champion’s fourth quarterfinal appearance at a WTA 1000 in 2026, as she continues to search for her first title of the year.Both players were tight out of the gate. It was their first meeting since the French Open round of 16, when Kostyuk beat Świątek in straight sets 7-5, 6-1. The opening set featured a pile of unforced errors and breaks of serve, and the first four games were breaks. The entire set featured a combined seven service breaks, with Świątek unable to hold.Świątek’s lone point on serve in the first set came in her opening service game, when Kostyuk sailed a forehand long. Otherwise, Kostyuk dominated on the return with powerful groundstrokes. Świątek couldn’t respond to Kostyuk’s pace, resulting in a lack of control in her shots. The errors consisted of shots long, wide or in the net. Serving down 3-4, Świątek double-faulted, paving the way for Kostyuk’s fourth break and ultimately the first set. Świątek was 1-for-11 in first-serve points won and 0-for-6 in second-serve points.After Świątek left the court to regroup, the match shifted. Świątek’s first-serve percentage remained the same (64.7 percent), but this time, more landed in (11 in the first compared to 22 in the second). Świątek struggled to place her serve in the first set, but it was nearly unreturnable in the final two. Up a break 2-0 in the second set, Świątek hit a body serve that Kostyuk couldn’t handle. The precision Świątek brought to her shots could not be said for Kostyuk. The mistakes piled up for the Ukrainian, the aggressiveness leading to balls sailing long or wide.