Jessica Pegula coasted into the US Open semi-finals on Tuesday with a straight-sets win over two-time Grand Slam champion Barbora Krejcikova.

The American fourth seed -- a beaten finalist in New York last year -- saw off the 62nd-ranked Krejcikova 6-3, 6-3 and is yet to drop a set at the tournament.

"I think I've been playing some really good tennis," said Pegula. "I feel like I'm just really comfortable."

Pegula will play reigning US Open champion Aryna Sabalenka or former Wimbledon winner Marketa Vondrousova on Thursday for a place in the final.

Krejcikova pulled off a miraculous escape in the last 16 when she saved eight match points against Taylor Townsend but ran out of steam against Pegula.

"We all saw what she did against Taylor, so I was happy that we're done," said Pegula.