Swiss third seed Roger Federer's Rome Masters bid ended at the third round with a 7-6 (7/2), 6-4 defeat to Austrian 13th seed Dominic Thiem on Thursday.

Federer, who withdrew last week from Madrid with back pain, admitted Wednesday he had been surprised to get past second round opponent Alexander Zverev in straight sets.

Rome marks only the fourth tournament of the season for Federer, who underwent knee surgery in early February, the first operation of his career.

The 17-time Grand Slam champion only decided to face Thiem at the last minute on Central Court, and the Austrian capitalised to finish off an obviously ailing Federer in 1hr 18mins.

In the quarter-finals, Thiem will now play either French 11th seed Richard Gasquet or Japan's sixth seed Kei Nishikori, who face off in a third round clash later Thursday.

It could be the beginning of a Rome Masters fairytale for the 22-year-old Austrian, who is approaching 30 wins for the season having secured two titles already and suffered defeat to Germany's Philipp Kohlschreiber in the final at Munich nearly a fortnight ago.

Later, defending champion Novak Djokovic faces Brazilian Thomaz Bellucci while seven-time winner Rafael Nadal plays Australian Nick Kyrgios.