World No. 19 Ekaterina Alexandrova collapsed on court and retired from her first-round match at the Memphis Classic as temperatures hit 34C. The top seed was trailing 7-6 (7-2) 4-6 5-4 against 16-year-old compatriot Kristina Liutova when the match was paused. After a time violation for taking too long to serve, Alexandrova fell mid-point and required medical attention. Though she could stand, the 31-year-old forfeited after more than three hours, handing Liutova a debut WTA victory that left the teenager in tears.

Elsewhere, Venus Williams fell in the first round of the Mubadala DC Open in Washington, D.C., losing 6-3 6-3 to Austria's Anastasia Potapova. The 46-year-old, whose last singles win came at this event last year, won 78.4% of first-serve points but only 24.1% on second serve and 20% of return points.