Federer's rejuvenation checked by Stepanek

Federer was powerless to prevent a thrashing from Rafael Nadal in the French Open final ( AP)

It was always a fair bet that a Swiss player would reach the last four of the Rome Masters, but few would have reckoned that the man in question would be Stanislas Wawrinka. As the Swiss No 2 reached his first Masters Series semi-final, Roger Federer yesterday suffered his sixth defeat of the year when he was beaten 7-6, 7-6 by Radek Stepanek.

If glandular fever was behind the world No 1's poor form at the start of the campaign, losing here was harder to explain. In his last two tournaments Federer had appeared to be on the way back to his best, but after winning his first title of the year in Estoril and losing in the Monte Carlo final to Rafael Nadal, this setback will rekindle speculation that he is at the start of a longer-term decline.

Stepanek, the world No 27, is an accomplished player with a good all-round game but Federer had beaten the 29-year-old Czech in their last four meetings and had reached the quarter-finals here without being unduly extended.

Federer seemed in relaxed mood as the first set meandered towards a tie-break, but from 4-4 the complexion of the match changed. A lovely stop volley gave Stepanek the chance to serve out for the set and he took it with a service winner and an ace.

With Federer's backhand misfiring badly Stepanek took a 4-1 lead in the second set, only for the Swiss to fight back and force another tie-break. Federer went two mini-breaks up at 4-1, but two more backhand errors let Stepanek back in and at 8-7 the Czech converted his second match point with a service winner. Today he will meet the winner of last night's quarter-final between Novak Djokovic and Nicolas Almagro.

Federer, who had hit more winners and fewer unforced errors than Stepanek and did not drop a point on his first serve until the start of the second set, said the defeat was hard to take. "I don't know if it was just the backhand," he said. "I missed plenty of opportunities throughout the match. I think I led in both breakers with a mini-break. I played so poorly on the big points."

Wawrinka, who knocked Andy Murray out in the second round and had also accounted for two former world No 1s, Juan Carlos Ferrero and Marat Safin, took two and a half hours to beat James Blake 6-7, 7-6, 6-1.

The 23-year-old, who plays the winner of yesterday's later quarter-final between Andy Roddick and Tommy Robredo, reached a career-high No 24 in the world rankings this week and will climb into the top 20 for the first time when an updated list is published on Monday.