American Jack Sock Collapses, Retires from Match Against Ruben Bemelmans at U.S. Open (VIDEO)

At USA Today, "American Jack Sock, overcome by heat, retires from U.S. Open":

NEW YORK — For the second straight year, American Jack Sock was done in by the heat and cramps at the U.S. Open on Grandstand.

Leading 6-4, 6-4, 3-6, 1-2 against world No. 107 Ruben Bemelmans, Sock suffered  cramps on the court, bringing the match to a halt. Sock, the No. 28 seed, had been given a point penalty because of his incapacity to serve at break point down at 1-1, handing the game to Bemelmans.

The trainer came out and assisted a grimacing Sock to the ground, who then motioned that he would opt out of the match.