American Taylor Fritz, the No 3 seed, advanced to the last eight of the Mexican Open by beating Canadian Denis Shapovalov 6-4, 6-4 at the Princess Mundo Imperial in Acapulco on Wednesday.
Fritz, ranked at a career-high No 5 in the world, will face fellow American Frances Tiafoe, the No 6 seed, next.
Fritz won the Delray Beach Open title earlier this month and is now on a six-match winning streak.
Ahead of his win today, Fritz had defeated compatriot John Isner (3-6, 6-3, 6-4).
Shapovalov, ranked No 30 in the world, edged out Serb Miomir Kecmanovic (6-7 (4), 6-0, 7-5) in the previous round of the Acapulco Open.
Acapulco ATP500, other second-round matches (Princess Mundo Imperial, hard, USD 2.013.940, most recent results first):
- Alex De Minaur (8) beat Jacopo Berrettini (Q): 6-1, 6-0
- Tommy Paul (7) beat Michael Mmoh: 6-4, 2-2 ret.
- Taro Daniel (Q) beat Casper Ruud (2): 7-5, 2-6, 7-6 (5)
- Frances Tiafoe beat Feliciano López (WC): 6-2, 7-6 (6)
- Mackenzie McDonald beat Brandon Nakashima: 6-2, 6-0
- Nuno Borges vs. Holger Rune
- Elias Ymer vs. Matteo Berrettini