Despite underperforming at the majors in 2014, Williams headed for the US Open with a spring in her step following an encouraging summer on the cement, featuring titles in Stanford and Cincinnati. She carried this rich vein of form into her opening matches, straight set wins over Taylor Townsend and Vania King booking a third round meeting with another of her compatriots, Lepchenko.
The Turning Point
For the majority of an entertaining contest that was far closer than the 6-3, 6-3 scoreline suggested, Lepchenko matched her opponent stroke for stroke. In the end, it was Williams' ability to deal with the wind - and the frustration caused by it - that helped subdue an often inspired opponent.
Unusually, Williams appeared happy to play second fiddle in the shotmaking department, employing a more conservative strategy to negate the tricky conditions. It paid dividends in the opening set, Lepchenko netting a backhand to give up the decisive break.
To the delight of the crowd, Lepchenko carried the fight into the second, raising her level and more than holding her own in a succession of rallies that sent both players scrambling to all corners of the court. But just as in the first set, it was the five-time champion's class that shone through at the pivotal moments, fending off two break points when trailing 3-2 before reeling off the next four games.
"I had to make some adjustments, but my coach gave me some excellent advice on playing in the wind, so I think I was able to play a lot better than the other day," Williams said. "My opponent today was spectacular. It was a really tough match and it just shows how far Varvara has come - I'm really proud of her.
"She really raised her game to an unbelievable level and I just tried to hang in there. I tried to remember what I needed to do and what I should do."
In the fourth round, Williams will face Kaia Kanepi, who upset No.15 seed Carla Suárez Navarro, 7-5, 6-0. Williams has won all three of their previous encounters, although the most recent of these came nearly five years ago.