Tiafoe upsets Del Potro at Delray Beach

DELRAY BEACH, Fla. (AP) 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). American Jared Donaldson fell to Denis Shapovalov of Canada, 7-6 (6), 4-6, 4-6.