Sam Querrey beats Rafael Nadal in Mexico

Big serving American Sam Querrey continued his fine form at the Mexico Open, downing Rafael Nadal to claim the title in Acapulco.

Big serving American Sam Querrey continued his fine form at the Mexico Open. (AAP)

American Sam Querrey dominated on serve to beat Rafael Nadal 6-3 7-6 (7-3) on Saturday night in the Mexican Open final.

Querrey had 19 aces to win his ninth career title. He's the first American champion in the history of the event.

The American had a great week beating favoured players on the road to the championship. He ousted fifth-seeded David Goffin, fourth-seeded Dominic Thiem and sixth-seeded Australian Nick Kyrgios on the way to the final against Nadal.

It was Querrey's first title since Delray Beach in 2016.

Nadal, the tournament winner in 2005 and 2013, had won 14 straight matches in Mexico.

On the women's side, the Ukraine's Lesia Tsurenko won her third career title, beating second-seed Kristina Mladenovic of France 6-1 7-5.

Tsurenko, the world's 50th player, won her first title since Guangzhou in September 2016.