Nadal to battle Djokovic, Serena to meet Errani
Spain's Rafael Nadal hits a return during the ATP-WTA Rome's Tennis Masters semi-final against Grigor Dimitrov of Bulgaria on May 17, 2014, at the Foro Italico in Rome - by Tiziana Fabi
Defending women's champion Serena Williams, meanwhile, will meet Italian Sara Errani after beating Serbian 11th seed Ana Ivanovic 6-1, 3-6, 6-1.
Djokovic, the number two seed, had ousted David Ferrer 7-5, 4-6, 6-3 in the quarter-finals on Friday when Nadal came through a tough clash with British number one Andy Murray.
But the Serbian, the world number two, was stretched over two tight sets by Canadian Milos Raonic, whose serves were regularly coming in just under the 230 km/h mark, before outlasting the eighth seed in a one-sided third.
"I can't recall the 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, 23, 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's efforts in a three-hour slug-fest with Raonic may have given the edge to Nadal, who despite playing late on Saturday made light work of Bulgarian Grigor Dimitrov in a 6-2, 6-2 win on Centre Court.
Statistically, the Serbian also has plenty of ground to make up on Nadal on the Spaniard's preferred surface of clay.
Overall, Djokovic has won 18 of the pair's 40 previous encounters, including the last three although they 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, Errani booked her place in the women's final to maintain her hopes of becoming the first Italian woman to win the tournament in 29 years.
Errani, seeded 10, had upset China's number two seed Li Na 6-3, 4-6, 6-2 on Friday and went on oust Serbian sixth seed Jelena Jankovic 6-3, 7-5 in their semi.
"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, who went on to lose last year's final to Williams.
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.
Raffaella Reggi was the last Italian woman to win the Italian Open in 1985.
But Errani is likely to need more than a partisan crowd to boost her on Sunday. The pair have met six times, and Williams has won on every occasion.
Williams, however, said: "She's improved, she taken her game to a different level. I have a lot of work to do tomorrow, she has nothing to lose, she has the crowd behind her."
Like Nadal, Williams is honing her French Open form, and she added: "The crowd won’t be a problem. It's a sort of warm-up for going into the French Open where the crowd is so intense, so I think this is the best thing I could have to get ready for that."