Cabo San Lucas, Baja California Sur, Mexico, 11 August 2016 | AAP

Bernard Tomic has gone down in his opening match in Los Cabos, Mexico.

Tomic, who entered the inaugural tournament as the second seed, lost to world No.72 Dusan Lajovic of Serbia 7-6(4) 3-6 6-4.

The world No.20 Australian was on song with his own serve in the opening two sets, but failed to send down an ace in the all-important third as he exited the tournament.

Tomic wasn’t the only seed to fall though; fourth seeded American Sam Querrey was beaten 7-6(1) 6-3 by Colombia’s Santiago Giraldo.

Spaniards Nicolas Almagro, Pablo Carreno Busta and Marcel Granollers, Croatia’s Ivo Karlovic and Frenchman Julien Benneteau all joined Lajovic and Giraldo in the quarterfinals.