ROME (Reuters) - Roger Federer's dreams of winning his first Rome Masters title ended when he slumped to a 6-2 6-4 defeat against Italian wild card Filippo Volandri in the last 16 on Thursday.
The world number one, who finished runner-up in Rome in 2003 and 2006, never found his rhythm against Volandri, dropping serve three times on the way to surrendering the first set.
He rallied briefly at the start of the second set, but four unforced errors in the third game -- the last two a long backhand and another into the net played almost casually -- allowed Volandri to grab another break and serve out for the match.
Federer's defeat means he has gone four tournaments without a title -- his longest stretch -- since becoming world number one in February 2004.
"It's disappointing, but there's nothing you can do about it. That's knock-out tennis," said a downcast Federer, denying he was ill or injured and dismissing the heat on Rome's centre court as a contributing factor to his defeat.
"I played good in my first match (to beat Nicolas Almagro), and usually after the first game I play better and better, but today was the opposite.
"On clay you need to be solid, and I wasn't. I don't know if you can say I was playing shockingly, but I was making a lot of mistakes, serving badly -- giving him second serves all the time.
"It sometimes happens, but usually I get through. And Volandri played well. Everyone is talking about how I played, but he already played well against (13th seed Richard) Gasquet (in the previous round).
"I know his game. I played a tough match against him here a few years ago, I played him in the juniors, so I know how tough he can be," added the Swiss.
Volandri, meanwhile, who has slipped back to 53rd in the world rankings after finishing last year inside the top 40, could hardly believe his win.
"What I've done here will only sink in tomorrow. This is the best court in the world. The crowd were fabulous," said Volandri.
"I played a perfect match and pushed all the way to the end. I couldn't ask anything more of myself."
Third seed Andy Roddick also fell in the last 16, losing 6-0 6-4 to claycourt specialist Juan Ignacio Chela.
The big-serving American, playing his first tournament since a hamstring injury forced him to pull out of the Miami Masters in March, could not match the metronomic groundstrokes of the Argentine.