Sam Groth has failed to join fellow Australians Bernard Tomic, Jordan Thompson and James Duckworth in the second round of the Sydney International after losing his first match in straight sets on Tuesday night.

The big-serving Groth lost 7-6 7-6 to world No.52 Federico Delbonis, cruelling what had been a fine day for Australia at the Sydney Olympic Park Tennis Centre.

Despite serving 16 aces to five, Groth struggled against Delbonis's ground game and the Argentinean squeezed out the victory.