Jessica Pegula is into the last four of a Grand Slam for only the second time Kena Betancur

Jessica Pegula said she had surprised herself by shaking off a poor run of form to reach the US Open semi-finals for the second year in a row on Tuesday.

The American fourth seed -- a beaten finalist in New York last year -- saw off Barbora 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," Pegula said after dispatching two-time Grand Slam champion Krejcikova inside Arthur Ashe Stadium.

"It's crazy to feel this comfortable on the biggest court in the world with the craziest crowd and the best players. It's something that 10 years ago I never thought I'd be good at this but I guess I am."

Pegula will play reigning US Open champi

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