Novak Djokovic battled into the Rome Masters final on Saturday after coming through a tough semi-final with Milos Raonic to beat the Canadian 6-7 (5/7), 7-6 (7/4), 6-3.
Djokovic, the number two seed, will face world number one Rafael Nadal in Sunday's final should the Spaniard defeat Bulgaria's Grigor Dimitrov in the second semi-final.
Djokovic had ousted David Ferrer 7-5, 4-6, 6-3 in the quarter-finals while Nadal came through a tough clash with British number one Andy Murray on Friday.
But the world number two was stretched by the hard-hitting Raonic, whose serves were regularly coming in just under the 230 km/h mark.
"I can't recall last time when I was feeling so helpless returning, even his second serves," said Djokovic.
The pair's only previous meeting came last year when Djokovic beat the Canadian 7-6 (7/1), 6-2, 6-2 in a Davis Cup semi-final rubber.
A year on from that win, Raonic left a much bigger impression on the six-time Grand Slam champion.
"He did surprise me with his movement, especially given his size, and he's got variety in his shots. You could feel the improvement in his game," he added.
Djokovic, who took exactly three hours to rack up his second win against Montenegrin-born Raonic in as many encounters, has won the Rome Masters twice, in 2008 and 2011.
Nadal is in the hunt for an eighth win in the Italian capital but Djokovic hopes Saturday's tough work-out will stand him in good stead.
"It is a big win because it gives me a lot of strength and belief that I can carry into tomorrow's final, and also for the rest of season," added the 26-year-old.
Overall, Djokovic has won 18 of his 40 previous encounters with Nadal, including the last three, although they all came on hard courts.
Of the duo's 16 meetings on clay, Nadal has won 13 including their last meeting on the surface at the semi-finals of the French Open in 2013.
Earlier, Sara Errani beat Jelena Jankovic 6-3, 7-5 to book her place in the women's final and maintain her hopes of becoming the first Italian woman to win the tournament in 29 years.
Errani, seeded 10, claimed her second consecutive semi-final place on Friday when she produced a stunning upset in overcoming China's number two seed Li Na 6-3, 4-6, 6-2.
Jankovic had accounted for Agnieszka Radwanska, the third seed from Poland, 6-4, 6-4 to reach the last four.
But the Serbian sixth seed was never in the match against 2012 French Open finalist Errani, who will appear in Sunday's final for the first time in her career.
"It was quite difficult out there, Sara played a great match and credit to her," said Jankovic.
"Overall it was a difficult day, I gave my best but there are a lot of things I could have done better."
Errani, 27, was ousted from the semi-finals last year by Victoria Azarenka.
But she admitted the home support was so intense she had to concentrate hard.
"I've never felt something like the before. The crowd were giving me so much support that it almost put me off," said Errani.
In Sunday's final she will meet either Jankovic's 11th seeded compatriot Ana Ivanovic or defending champion and top seed Serena Williams.
Raffaella Reggi was the last Italian woman to win the Italian Open in 1985.