HOUSTON (AP) — Defending champion Frances Tiafoe beat James Duckworth 6-2, 6-7(4), 7-5 on Thursday night in the U.S. Men's Clay Court Championship to advance to the quarterfinals for the third straight year.

The third-seeded American had 15 aces and didn't face a break point against the Australian.

"Every win is big right now, to just kind of build it," Tiafoe said. "Tonight was huge."

He improved to 8-7 this season.

"I wish I won in straights, but I definitely played pretty well," Tiafoe said. "I thought I played really well in the first set. He can serve really well. I had some chances, some break points, but good serves from him and he really made it tough for me."


Tiafoe advanced to face sixth-seeded Jordan Thompson of Australia in the quarterfinals Friday. Thompson beat American Aleksandar Kovacevic 4-6, 7-6(1), 7-6(7) in 3 hours, 35 minutes in the longest match in tournament history.

Also, fourth-seeded Tomas Martin Etcheverry of Argetnina beat Daniel Elahi Galan of Colombia 6-4, 6-4. American Michael Mmoh upset eighth-seeded Max Purcell of Australia 6-2, 7-5.