Pegula, who enjoyed a superb run to the final at Flushing Meadows 12 months ago, looked much closer to her best on Sunday as she broke the serve of Li six times on her way to victory.
“I know when she’s serving well and has confidence she’s really dangerous,” Pegula said of Li, who she beat in a much tighter match at the French Open back in May.
“I felt like she came out a little slow and nervous and I wanted to jump on that and not let her feel comfortable for a second, that was my motivation all match.”
Li represented a potentially tricky opponent despite her world ranking of 58, ranking second for aces with 22 from her first three matches.
The 25-year-old appeared confident as she chose to serve first after winning the coin toss, only for Pegula to break immediately.
Li improved after making 10 unforced errors and winning just 8% of her second serves during the first set, but Pegula seemed to raise her own game in response.
Pegula was strong on the baseline as usual, but she made a conscious effort to move to the net as well. By contrast, Li tended to stay deep in a fruitless effort to keep up with Pegula’s powerful strokes.
“I felt really comfortable moving in today and coming in at the right times. It doesn’t always feel that good, but it started well and I wanted to keep executing that until the last game,” said Pegula.
“It’s a part of my game I can really use as a weapon. Sometimes I get stuck at the back because I’m so good there, but we’ve worked on that a lot and my coaches are happy when I’m finishing overheads and volleys at the net.”
In the quarter-finals Pegula will face world number 62 Krejcikova, who is a player not to be underestimated.
