Serena Williams roars into US Open quarters

In the quarterfinal, Serena will meet 2016 US Open runner-up Karolina Pliskova, who beat Serena in the U.S. Open semifinals that year.

"I really was feeling great that year. I'm feeling great now, too. But it was a little bit different story, 2016. I was, like, a dark horse. Nobody was expecting me to get that far," Pliskova said after beating No 18 Ashleigh Barty 6-4, 6-4.