DELRAY BEACH, Fla. -- American wild-card Frances Tiafoe saved 14 of 16 break-point chances to edge No. 2-seeded Juan Martin del Potro 7-6 (6), 4-6, 7-5 Thursday night in the second round of the Delray Beach Open.
Tiafoe hit 17 aces and won a three-setter for the fourth time this month.
No. 8 Chung Hyeon became the highest-seeded player to reach the quarterfinals when he eliminated Franko Skugor 6-4, 7-6 (4). Canadian Denis Shapovalov beat American Jared Donaldson 6-7 (6), 6-4, 6-4.