Nestor combined with Australian Bernard Tomic for a 7-6 (7), 6-3 victory over Nestor and new partner Robert Lindstedt of Sweden on Thursday in quarter-final action at the Monte Carlo Masters.
Raonic, 22, and Tomic had to battle to get past 40-year-old Nestor as he played his first event with new partner Robert Lindstedt of Sweden, with the pair seeded third.
Raonic, form Thornhill, Ont., also beat Toronto's Nestor last month in the first round at the Indian Wells Masters alongside Spain's Feliciano Lopez. That one-off team beat Nestor and Mahesh Bhupathi in straight sets on the California hardcourts.
Raonic is trying to play in all of the clay matches he can as he prepares for the French Open.
"The match was good," Raonic said. "Bernie and I played well, we were there for all the big points. We stuck around and made the most of it. I'm glad we held on and played well."
Raonic, ranked 15th in the world, will play singles next week in the ATP clay event at his training base in Barcelona, where he works with Spanish coach Galo Blanco.
Raonic and the 20-year-old Tomic combined for 10 aces between them in the 76-minute victory. One break in the match made the winning difference, with the unseeded youngsters saving both of the break points they faced.
The winners now have a day off as they wait for an opponent form either the top-seeded American Bryan brothers or Austrian Jurgen Melzer and Indian Leander Paes.
Raonic said that more time on clay can only help his singles game.
"I take every match very seriously — doubles I take seriously," Raonic said.
"But at the same time I use it more as a way at this point to build for my singles. Here it's really about getting as many matches on clay as possible."
Raonic and Tomic needed nearly an hour to win the rugged opening set in a tiebreaker, then secured their winning break in the second set to reach the final four.
The semi is the first in doubles for Raonic since Halle, Germany, in June, 2011, when he and Robin Hasse reached the final on grass at the pre-Wimbledon event.