Top-seeded Simona Halep was forced to retire due to heat exhaustion while losing her quarterfinal match against Ekaterina Makarova at the Citi Open on Friday at Washington.
On-court temperatures reportedly soared up to 116 degrees and Halep withdrew after losing the first game of the final set, giving Makarova a 2-6, 6-3, 1-0 victory that pushed the Russian into Saturday's semifinals.
Halep rolled through the opening set before the seventh-seeded Makarova recovered to win the second set. Halep was notably sluggish in the later stages and called for a tournament doctor during the changeover.
Makarova rolled through the opening game of the third set and the Romanian decided she could no longer continue.