NEW YORK (AP) Caroline Wozniacki won her U.S. Open semifinal when Peng Shuai retired because of apparent heat illness.
Wozniacki was up a set and a break Friday on an extremely humid afternoon when Peng stumbled to the wall behind the baseline with what seemed to be severe cramping in her legs.
She was helped off the court and after a 10-minute delay returned to try to keep playing.
Six points later, Peng collapsed to her knees. Wozniacki walked to the other side of the court to pat her on the back before the decision was made that Peng couldn't continue.
Wozniacki watched through tears as Peng was taken off in a wheelchair.
This is Wozniacki's first major final since the 2009 U.S. Open, when she lost to Kim Clijsters.