A traffic-jam opening set between Linda Noskova and Marta Kostyuk—featuring eight breaks of serve before Kostyuk took control in the tiebreak—gave way to a runaway second set, as the Ukrainian surged to a 7-6(1), 6-0 victory to reach her second WTA 1000 semifinal at the Caja Mágica.
Kostyuk, the champion in Rouen nine days ago, extends her career-best winning streak to nine and sets up a semifinal clash with Anastasia Potapova.
Kostyuk seized control in her first career meeting with the 13th-ranked Czech behind a relentless return game, earning a remarkable 24 break points and converting seven.
She then tightened her serve in the second set, not facing a single break point as she improved to 15-4 on the season.
Kostyuk has yet to drop a set in Madrid—her run includes a 6-2, 6-4 win over No. 5 Jessica Pegula in the third round. She also defeated Yulia Putintseva, 6-1, 6-3, in round two, and Caty McNally, 6-2, 6-3, in the round of 16.