NEW YORK — Seven months after his grand slam debut, journeyman Jason Jung recorded the biggest scalp of his career when he upset Frances Tiafoe 6-3, 7-5 in the second round at the New York Open on Thursday.

After squandering a match point while receiving at 5-3, Jung was broken in the next game and the match seemed to be slipping from his grasp at the Nassau Coliseum on Long Island.

But American-born Jung, who plays for Taiwan, regrouped and broke back in the next game before serving out for the win, reacting in subdued fashion with nothing more than a little fist pump.

World No. 143 Jung is ranked 114 spots below Tiafoe, but played well above his station against the American, who perhaps was a little underdone after not playing since his Australian Open quarterfinal loss to Rafa Nadal three weeks ago.

Second seed Tiafoe was a late entry into the New York Open. His departure leaves only one of the top five seeds left in No. 1 John Isner.

Jung, 29, has never been ranked in the top 100 and perhaps is best known for getting a lucky loser spot at Wimbledon last year for his first grand slam main draw appearance when Andy Murray pulled out injured.

Next up for Jung in a Friday afternoon quarter-final is American sixth seed Sam Querrey, who earlier defeated Radu Albot of Moldova 6-3, 6-4.

Thursday's evening quarterfinal pits American Isner against Australian Jordan Thompson.

In other quarters, Italian Paolo Lorenzi meets Canadian Brayden Schnur, while Spaniard Guillermo Garcia-Lopez takes on American Reilly Opelka. — Reuters