Top-seeded Stefanos Tsitsipas of Greece outserved big-hitting American John Isner on Wednesday en route to a 6-3, 6-2 win in the second round of the Abierto Mexicano Telcel in Acapulco, Mexico.
Tsitsipas won 24 of his 25 first-serve points and never faced a break point. Isner won just 19 of 32 first-serve points and had his serve broken three times.
Second-seeded Alexander Zverev of Germany topped Serbia's Laslo Djere 6-4, 6-3, and fifth-seeded Grigor Dimitrov of Bulgaria, seventh-seeded Felix Auger-Aliassime of Canada and eighth-seeded Casper Ruud of Norway also advanced to the quarterfinals.
Germany's Dominik Koepfer upset fourth-seeded Milos Raonic 6-4, 6-2, and Great Britain's Cameron Norrie eliminated sixth-seeded Fabio Fognini of Italy 6-4, 6-4. In the lone match featuring two unseeded players, Italy's Lorenzo Musetti rallied past the United States' Frances Tiafoe, 2-6, 6-3, 7-6 (1).
Dubai Duty Free Tennis Championships
Second-seeded Andrey Rublev of Russia needed just 64 minutes to rout 15th-seeded Taylor Fritz of the United States 6-3, 6-1 in the third round at Dubai, United Arab Emirates.
Rublev never lost his serve while racking up 12 aces to Fritz's six. Rublev's quarterfinal opponent will be Hungary's Marton Fucsovics, who topped 11th-seeded Dusan Lajovic of Serbia 6-1, 4-6, 6-4.
Third-seeded Denis Shapovalov of Canada dumped 13th-seeded Hubert Hurkacz of Poland 6-4, 6-3. Sixteenth-seeded Jannik Sinner of Italy knocked off fourth-seeded Roberto Bautista Agut of Spain 6-4, 3-6, 7-5, but eighth-seeded Karen Khachanov of Russia, 14th-seeded Filip Krajinovic of Serbia and 17th-seeded Lorenzo Sonego of Italy were upset.
--Field Level Media