American Jessica Pegula says completing an escape room with friends helped her rediscover her form and embark on a run to the US Open quarter-finals.

Fourth seed Pegula needed just 54 minutes to beat a nervous Ann Li 6-1 6-2 on Sunday and keep alive her hopes of winning a career-first Grand Slam.

In the last eight she will face 2024 Wimbledon champion Barbora Krejcikova, who saved eight match points on her way to beating home hopeful Taylor Townsend 1-6 7-6 (15-13) 6-3 in a thrilling match.

Pegula, 31, has endured a difficult summer, with a humbling first-round exit at Wimbledon followed by early round exits at WTA events in Washington, Montreal and Cincinnati.

“I felt terrible coming into this tournament, honestly,” Pegula said after beating compatriot Li.

After quitting midway through a practice session with world number one Aryna Sabalenka days before the US Open, Pegula’s mood improved after a night out with friends.

“[We] went and did an escape room with my friends and had, like, two drinks and [realised] I need to just chill and stop getting so frustrated and overthinking all these practices,” she said.

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 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.”