Paris: Bernard Tomic's French Open is over after a straight-sets first-round loss to sixth-seed Dominic Thiem.

Tomic capitulated after a competitive first set, falling 6-4 6-0 6-2 in stifling day-one conditions in Paris.

Thiem was always going to be a tough ask for Tomic, with the Austrian among the chief threats to Rafael Nadal's quest for a 10th title after ending the Spaniard's 17-match winning streak in Rome 10 days ago.

Tomic made his game plan clear from the outset, pulling the trigger early in rallies to hold his opening service game.

He then had Thiem under pressure at 0-30 in the second game of the match, but the world No.7 survived before gaining the first break in the fifth game.

The Australian No.2 continued to fight hard throughout a tight opening set before winning just seven points in the second and starting to complain about the sticky 32-degree heat.

There was no coming back after he dropped serve for a fifth time to slip 3-1 behind in the third set.

Tomic raised his racquet in appreciation of Thiem's wizardry after the Austrian won the rally of the match with a tweener and round-house forehand pass in the following game.

Thiem snared another break for 4-1 before powering to victory in 80 minutes to book a second-round meeting with either Nicolas Mahut or Simone Bolelli.

AAP