Second seed Juan Carlos Ferrero and fourth seed Roger Federer set up a semi-final showdown in contrasting styles at the Rome Masters on Friday.
While Ferrero cruised to a 6-4, 6-4 victory over Germany's Rainer Schuettler in his quarter-final match, Federer dropped a set for the first time in his last nine claycourt matches before beating home favourite Filippo Volandri 6-3, 5-7, 6-2.
The winner of their match will face either Russia's Yevgeny Kafelnikov, who beat Martin Verkerk 6-3, 7-5, or Felix Mantilla, who defeated Ivan Ljubicic 3-6, 6-3, 6-4.
Kafelnikov and Mantilla are attempting to become the first unseeded player to win the Rome tournament since the open era began in 1968.
Federer looked shaky at the start of his match against Volandri, mistiming a series of backhands to drop serve in the third game before he broke back immediately and capitalised on the Italian's mistakes to wrap up the first set in 36 minutes.
The 21-year-old Swiss again recovered from a break down in the second set, but as he served to level in the 12th game, Volandri dug out a tricky crosscourt pass to create break point.
Federer then netted another tame backhand to lose the set and level the match.
The decider proved more straightforward, with Federer breaking twice to continue his challenge to add the Rome title to wins in Marseille, Dubai and Munich this year.
"I don't think I should have lost the (second) set the way I did, getting broken after leading 30-15 and with a chance to go 40-15 up," he told reporters after the match. "I missed a few stupid shots, but he hung in tough."
Ferrero, meanwhile, enjoyed a smoother passage to the semi-finals with an easy victory over Australian Open finalist Rainer Schuettler, who was dragged round Rome's slow clay court by the Spaniard's relentless groundstrokes.
Having wrapped up the first set in a little over half an hour, Ferrero then broke in the ninth game of the second set and served out for the match.
The victory continued the Spaniard's excellent 2003 record on clay of 21 wins from 22 matches and titles in Monte Carlo and Valencia.
"Tomorrow I'm going to try to play very aggressive all the time, you know, try to return his big serve," said Ferrero. This is the first time we've met on a clay court, so we'll just see what happens."
Ferrero has beaten Federer twice in three previous encounters, though the Swiss triumphed in their last meeting at last year's season-ending Masters Cup in China.
The winner of the Ferrero-Federer match will have to meet either a resurgent Kafelnikov or the unheralded Mantilla in the final.
Former world number one Kafelnikov has already accounted for 16th-seed Younes El Aynaoui and third seed Carlos Moya this week and against Verkerk on Friday, the 1996 French Open champion succeeded where fifth seed Andy Roddick failed by nullifying the the Dutch qualifier's huge serve.
He maintained the pressure throughout the match, harrying Verkerk into double faults to gain crucial breaks in the eighth game of the first set and the 11th game of the second.