Defending champion Sam Querrey advanced to the second round of the Los Cabos Open with a 6-2 6-3 win over Mexican Lucas Gomez.

Querrey – the fifth seed – fired down nine aces to dispatch local hope Gomez in straight sets on Tuesday as he stepped up his preparation for the US Open later this month.

The American won the ATP 250 event last year when he defeated Australian Thanasi Kokkinakis in the final, and will hope to replicate the form he subsequently showed at Flushing Meadows when the 30-year-old became the first local man to reach a quarter-final in New York since 2011.

Querrey faces Egor Gerasimov in the next round after the lowly-ranked Belarusian knocked out former world number 17 Bernard Tomic in straight sets.

Tomic had four break points, but the Australian was unable to convert any of his opportunities as he fell to a 6-4 6-3 defeat after just over an hour on court.

Meanwhile, Cameron Norrie backed up a run that saw him reach the Atalanta Open semi-final last week with a 6-2 6-2 win over Prajnesh Gunneswaran.

Norrie will meet eighth seed Feliciano Lopez in the round of 16 after the 36-year-old Spaniard defeated Egyptian Mohamed Safwat 7-6 (7-3) 6-4.

Elsewhere, Peter Polansky beat Daniel Galan in 6-4 3-6 6-2, while American qualifier Marcos Giron eased past Marcelo Arevalo 6-2 7-5, while Quentin Halys eliminated Gilles Muller 6-4 6-4.