ROME -- Roger Federer was not concerned after losing to 15th-ranked Dominic Thiem 7-6 (2), 6-4 in the third round of the Italian Open on Thursday.
After withdrawing from last week's Madrid Open with lower back pain, Federer was just glad he was able to play two matches on the clay in Rome.
"It doesn't matter how I played. (What is) important is that I didn't have any setbacks and I was able to step on the tennis court and that I tried what I could with what I had," said Federer, who defeated German teenager Alexander Zverev in straight sets on Wednesday.
"I knew I wasn't good enough for any result here, so that's why I hope you don't read into it so much and I don't," Federer said. "This is like, 'Who cares about the results here?' It matters what comes now in the next couple of months."
With only 10 days before the French Open, however, Federer needs to figure out how to manage the pain.
"Time starts ticking more towards Paris," said Federer, who also missed 10 weeks this year after surgery on his left knee to repair a torn meniscus. "The way I'm playing right now is never going to be enough for any good run in Paris, and then I also wouldn't play this way. I'm still confident I will be fine somehow."
In the quarterfinals, Thiem will face sixth-seeded Kei Nishikori, who beat Richard Gasquet 6-1, 6-4.
Seven-time Rome champion Rafael Nadal ground past Nick Kyrgios 6-7 (3), 6-2, 6-4, and will next face Novak Djokovic or Thomaz Bellucci, who played late.
Also, Juan Monaco of Argentina upset French Open champion Stan Wawrinka 6-7 (5), 6-3, 6-4 and lucky loser Lucas Pouille beat ninth-seeded David Ferrer 6-4, 6-1.
In the women's tournament, top-ranked Serena Williams came back from 5-3 down in the opening set and saved a set point in the tiebreak to beat American qualifier Christina McHale 7-6 (7), 6-1.
Williams was sick on Wednesday after trying some of her dog's food, but said she felt fine on Thursday.
"Unfortunately, it was true," said Williams, who first shared the news on Snapchat. "I'm not the most serious person off the court. On the court I am, but off the court I don't have a serious bone in my body."
Williams' quarterfinal opponent will be Svetlana Kuznetsova, who beat Daria Gavrilova 6-2, 2-6, 6-3.
Also, Timea Bacsinszky beat eighth-seeded Carla Suarez-Navarro 5-7, 7-5, 6-2; Irina-Camelia Begu defeated Daria Kasatkins 6-1, 6-4; and Misaki Doi of Japan eliminated Johanna Konta of Britain 4-6, 7-5, 6-2.
Federer went up a break early in the first set but Thiem broke right back and Federer made little impact on the Austrian's serve the rest of the way, deciding not to run back to the middle of the court after a couple of weak backhand returns -- heading straight for his chair instead as Thiem hit easy winners into the open court.
At 22, Thiem is the youngest player in the top 20 rankings, and second to Djokovic in wins on tour this year.
In the second set, Federer attempted his "SABR" -- "sneak attack by Roger" -- return strategy by rushing forward a couple of times to try to pick up Thiem's serve near the service line. On one such occasion, Federer got the return back with his frame, setting up an overhead winner.
Federer also attempted to follow his serve to the net more in the second set but eventually gave up the tactic when Thiem started passing him with explosive returns.
"For the first time maybe I could play a match really just playing freely, trying out a few things," Federer said. "Obviously I was limited because Thiem had completely the upper hand from the baseline so I had to find other ways to win the point. That was interesting in itself."
Rome remains one of the few important tournaments that Federer has never won. He's a four-time runner-up at the Foro Italico, including last year.
