DELRAY BEACH, Fla. (AP) — American qualifier Christian Harrison upset top-seeded Cristian Garin of Chile 7-6 (3), 6-2 Saturday in the second round at the Delray Beach Open.
Harrison, ranked No. 789, squandered three consecutive set points serving at 6-5 in the first set and lost serve, but regrouped to dominate the tiebreaker. He swept the final four games of the match to become the second-lowest-ranked quarterfinalist in tournament history.
Juan Martin del Potro was ranked No. 1,042 when he reached the quarters in 2016.
No. 2-seeded John Isner of the United States hit 22 aces, never faced a break point and beat Thiago Monteiro of Brazil, 6-4, 7-6 (4). Isner next plays Sebastian Korda, who rallied to win an all-American match against No. 5 Tommy Paul, 4-6, 6-3, 6-2.