Los Cabos - Juan Martin del Potro opened his summer hard-court season with a 7-5, 6-3 victory over American Marcos Giron on Wednesday night in the Mifel Open.
Playing for the first time since losing to Rafael Nadal in the Wimbledon quarter-finals, the top-seeded del Potro set up a quarter-final match against Egor Gerasimov.
Del Potro won hard-court titles this year at Indian Wells and Acapulco. The fourth-ranked Argentine star has 22 career victories, the biggest on a hard court in the 2009 US Open.
Gerasimov, from Belarus, outlasted fifth-seeded defending champion Sam Querrey of the United States 7-5, 5-7, 7-6 (6). Querrey swept the Los Cabos and Acapulco events last year.
Fourth-seeded Adrian Mannarino of France topped Sweden's Elias Ymer 6-0, 6-2. The Frenchman will play Cameron Norrie, the British left-hander coming off a semi-final appearance in Atlanta. Norrie beat eighth-seded Feliciano Lopez of Spain 6-3, 6-3.
Japan's Yoshihito Nishioka also knocked off a seeded player, topping seventh-seeded Taylor Fritz of the United States 7-6 (3), 6-1. Nishioka will face second-seeded Fabio Fognini of Italy.
Third-seeded Damir Dzumhur of Bosnia and Herzegovina got past Italy's Thomas Fabbiano, 7-6 (0), 7-6 (5). He'll play American Michael Mmoh, a 7-6 (1), 7-6 (2) winner over Canada's Peter Polansky.
Results from ATP Los Cabos Open tournament on Wednesday (x denotes seed):
Juan Martn Del Potro (ARG x1) bt Marcos Giron (USA) 7-5, 6-3
Egor Gerasimov (BLR) bt Sam Querrey (USA x5) 7-5, 5-7, 7-6 (8/6)
Damir Dzumhur (BIH x3) bt Thomas Fabbiano (ITA) 7-6 (7/0), 7-6 (7/5)
Michael Mmoh (USA) bt Peter Polansky (CAN) 7-6 (7/1), 7-6 (7/2)
Cameron Norrie (GBR) bt Feliciano Lopez (ESP x8) 6-3, 6-3
Adrian Mannarino (FRA x4) bt Elias Ymer (SWE) 6-0, 6-2
Yoshihito Nishioka (JPN) bt Taylor Fritz (USA x7) 7-6 (7/3), 6-1
Fabio Fognini (ITA x2) bt Quentin Halys (FRA) 2-6, 6-4, 6-0