The second set was a different story than the first, as Anett Kontaveit settled down and Serena Williams began making more unforced errors. 

The capacity Arthur Ashe Stadium crowd, sensing a lost set for Williams, fell quiet.

Kontaveit found her rhythm early and often, breaking Williams easily in the first game and smashing winners all over the court.

Williams, trying to pump herself up, yelled “Come on!” in game 3 after hitting some winners of her own. But Kontaveit held steady to take a 3-0 lead and mostly cruised from there.

Williams is almost 41 and has battled a host of injuries in recent years. Her game is not as consistent as it was five years ago. And yet throughout the set, she showed flashes of her familiar brilliance, chasing down shots and pounding cross-court winners.

Williams' serve was her biggest weapon, as she struck 10 aces. But it also betrayed her at key moments, as when she double-faulted on game point to go down 4-1.

Williams took a brief break after the set, going to the locker room for a few minutes before returning to the court.