ROME: Dominic Thiem claimed his fourth Top 10 win on Thursday at the Foro Italico in Rome as he upset Roger Federer 7-6(2), 6-4 to reach the quarter-finals of the Internazionali BNL d’Italia. The 22-year-old Austrian will look to reach his first ATP World Tour Masters 1000 semi-final when he faces Kei Nishikori on Friday. Hindered by a back injury, Federer was not at his best, but Thiem stepped up and held his nerve to oust the 34-year-old Swiss in 79 minutes. Thiem rallied from a break down in the first set and big ball striking from the right-hander in the tie-break opened up a 6/2 lead. He closed out the opener with a backhand winner down the line. Thiem broke for a 3-2 lead in the second set as he chased down a Federer drop volley to rifle home a forehand winner. The Austrian went on to seal his 32nd match win of the season (32-9 record), the second most wins on the ATP World Tour this season behind Djokovic. “I’m very happy to be in the quarter-finals, it was a very tricky match today,” said Thiem, who struck 29 winners to 13 unforced errors. “Of course he was not 100 per cent, but still, he played some very good points. I think you cannot put it out of your head. It’s impossible, I think.” Thiem is through to his second ATP World Tour Masters 1000 quarter-final, having reached his first last year in Miami (l. to Murray). The Austrian has already played three finals this year, lifting trophies in Buenos Aires – where he beat Rafael Nadal in the semi-finals) – and Acapulco and finishing runner-up in Munich (l. to Kohlschreiber). Federer, a four-time finalist in Rome, was looking to tie Ivan Lendl with 1,071 wins on the Open Era list. The Swiss has been hampered by injury in 2016. After reaching the Australian Open semi-finals, Federer was forced to undergo arthroscopic left knee surgery to repair a torn meniscus. He returned from a 10-week absence in Monte-Carlo, where he reached the quarter-finals, but then had to withdraw from the Mutua Madrid Open due to a back injury. The sixth-seeded Nishikori was a 6-1, 6-4 winner over 11th seed Richard Gasquet, whom he had only beaten once in their previous seven meetings. After leading 4-1 in the second set, Nishikori held off a Gasquet fightback as the Frenchman rallied to level at 4-4, before Nishikori won the final two games of the match. Nishikori won his one previous meeting with Thiem, on grass in Halle last year, and is looking to reach the semi-finals in Rome for the first time. He was beaten in the quarter-finals last year by Novak Djokovic.