Stricken by cramps, a dazed and disorientated Sock is helped off court retiring from second round vs. Ruben Bemelmans.
Former US Open champion couldn't get a courtesy car, but still cruised into third round.
After his straight-sets win over Andreas Haider-Maurer, Novak Djokovic got busy on the dance floor.
Belinda Bencic lost her composure after some difficult moments, but rallied to advance in three sets vs. Misaki Doi.
CoCo Vandeweghe's most ferocious shot of the second round came when she obliterated her Yonex stick.
"I think (Rafa's) gonna be okay. If not this year then next year," No. 18-seeded Lopez said at US Open.
In just two days of the US Open, we've already seen the longest women's match and a record for retirements in the first round.