Tiafoe was the No. 2 seed after accepting a wild card into the field and lost after having a first-round bye while two other Americans reached the quarterfinals.
UNIONDALE, N.Y. — Frances Tiafoe lost his first match since the Australian Open quarterfinals, falling to Jason Jung of Taiwan 6-3, 7-5 on Thursday night in the second round of the New York Open.
Tiafoe was the No. 2 seed after accepting a wild card into the field and had a first-round bye. The American has a career-high ranking of No. 29 after his run in Melbourne, where he lost to Rafael Nadal.
No. 4 seed John Millman of Australia was also upset, losing 7-6 (4), 1-6, 6-4 to Guillermo Garcia-Lopez of Spain.
Two other Americans reached the quarterfinals. No. 6 seed Sam Querrey, a finalist last year on Long Island, beat Radu Albot of Moldova of 6-3, 6-4. Reilly Opelka advanced when Denis Istomin of Uzbekistan was forced to retire after they split a pair of tiebreakers.