Rafael Nadal came through the toughest test of his clay-court season to defeat Nikolay Davydenko 7-6 (7-3) 6-7 (8-10) 6-4 in the Rome Masters semi-finals.
Nadal had his toughest match to date at this year's Foro Italico
It was a 76th consecutive victory on clay for the Spaniard, breaking John McEnroe's one-surface record.
But Nadal was tested to the limit as he saved a set point in the first set, failed to serve out the second and let an early lead slip in the decider.
Fernando Gonzalez beat Filippo Volandri 6-1 6-2 in Saturday's first semi-final.
Nadal arrived in Rome having won clay titles in Monte Carlo and Barcelona, and such was his dominance that he had yet to lose a set on the surface in 2007.
It was one of the most difficult matches I've ever played on clay
World number four Davydenko was able to match Nadal's hitting from the baseline though, and three times he fought back from a break down before earning a set point in the opener.
When the Russian failed to convert and Nadal dominated the ensuing tie-break, it suggested another straight-sets win was on the cards.
But the super-fit Davydenko was relentless and there were the first suggestions that 20-year-old Nadal might be struggling to keep pace after such a long run of victories.
Nadal failed to serve out the match at 5-3 and in a dramatic second tie-break it was Davydenko who dictated, finally levelling after six set points.
It had taken two and a half hours to play just two sets and there was every reason to believe that Nadal would be the more tired in the decider.
But the world number two showed all his fighting qualities in the final set.
He broke to love in game nine before serving out the match after three hours, 38 minutes and collapsing to the floor as though he had won the title.
"It was one of the most difficult matches I've ever played on clay," said Nadal. "I really risked losing it."
Davydenko said: "He tried for every ball - it's amazing. It was my body. My shoulder was tired. I'm not like Nadal physically. I need to improve physically. My tennis is not so bad."
Although Nadal will be the favourite to win a third consecutive Rome Masters title on Sunday it may prove a tough task after Gonzalez breezed into the final for the loss of just three games.
"I'm confident," said the Chilean sixth seed. "I have nothing to lose and he's the man with the record. He's a great player and a good athlete, but I will try my best.
"He's played in many finals and he's going to be a tough guy to beat, but I have been playing really well in my last two matches and I like the conditions here."