Roger Federer has been eliminated from the Italian Open, losing to 15th-ranked Dominic Thiem in the third round.
Federer withdrew from last week's Madrid Open with lower back pain and has only 10 days before the French Open begins.
He went down 7-6 (7-2) 6-4 on Thursday to the rising young gun.
Federer went up a break early in the first set but Thiem broke right back and the Swiss 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.
At 22, Thiem is the youngest player in the world top 20 and he advances to the quarter-finals in Rome.
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The win in just 78 minutes avenges the 22-year-old's heavy loss to the 17-time grand slam champion at the start of the year in a Brisbane semi-final.
Federer came to the court still unsure of his form after dealing with the back pains which forced him out of Madrid. He was playing in only his fourth tournament of the season after knee surgery in early February.
Federer still stands a match away from tying Ivan Lendl with 1071 wins in the Open era, a record he will have to try to approach at the French Open.
The 15th-ranked Thiem earned his 32nd victory of the season, the second-most wins behind top seed Novak Djokovic (34).
The Austrian's victory was his fourth career win over a top-10 opponent, as Federer had 34 unforced errors and just 18 winners. The Swiss converted on only one of his three break points.
