Medvedev defeated Karen Khachanov 6-1, 7-6 (6) in the first of Saturday’s two semifinals at IGA Stadium.
The top-seeded Nadal, from Spain, was scheduled to take on Gael Monfils of France in the other semifinal of the US$5.7-million ATP Tour Masters 1000 series event later Saturday, but the latter withdrew because of an ankle injury.
The final, which goes Sunday afternoon, will be the first-ever meeting between Medvedev and Nadal.
Khachanov, the No. 8 player in the world, was broken by his fellow Russian twice in a first set that took just 23 minutes.
Ranked right behind Khachanov at No. 9, Medvedev broke his opponent for a third time to go up 2-1 in the second set. But Khachanov broke right back and led 3-2 at the changeover.
WATCH: Bianca Andreescu advances to Rogers Cup finals
Medvedev broke Khachanov again to go up 5-4 only to give it right back serving for the match in the next game.
Then up 7-6 in the tiebreak, Medvedev sealed it when his shot clipped the net and bounced in, ending a match that took one hour 23 minutes.
Robin Haase and Welsley Koolhof of the Netherlands defeated Denis Shapovalov of Richmond Hill, Ont., and India’s Rohan Bopanna 7-6 (3), 7-6 (7) in doubles semifinal play, and will now take on Spain’s Marcel Granollers and Argentina’s Horactio Zeballos in Sunday’s final.
Shapovalov, who went on a memorable run to the Rogers Cup semis in Montreal in 2017, lost to Thiem in the second round of this year’s singles competition.
Medvedev, who lost last week’s final in Washington to Nick Kyrgios, is the first Russian to make the title showdown of the men’s tournament since Marat Safin won the event back in 2000 when it was called the du Maurier Open. Saturday also marked was the first time in the 30-year-old history of the Masters 1000 Series that two Russians had competed in a semifinal.
Medvedev and Khachanov — both 23, six foot six and from Moscow — advanced to the semis with ease Friday. Medvedev breezed to a 6-3, 6-1 upset of world No. 4 Dominic Thiem of Austria in the quarters before Khachanov followed with a 6-3, 6-3 decision over No. 7 Alexander Zverev of Germany.
Back in June, Khachanov became the first Russian to crack the top-10 since Mikhail Youzhny in February 2011. Medvedev then joined him there on July 15.
WATCH: Quebec teen tennis sensation is fan favorite at Rogers Cup
Born just over three months apart in 1996, they squared off in the semis of their hometown tournament in the duo’s only previous tour meeting last October, which Khachanov won 6-1, 6-7 (5), 6-3.
Monfils, ranked No. 20, and No. 13 Roberto Bautista Agut of Spain were forced to play their weather-delayed quarterfinal Saturday afternoon — more than 18 hours after they left centre court when the skies opened up early in Friday’s first set.
Monfils beat Bautista Agut 6-4, 3-6, 7-6 (2) despite battling a sore left ankle much of the match, which lasted two hours 24 minutes following another lengthy rain delay.
After consulting with his coach, Monfils made the decision to withdraw from the semis.
“He said ‘You can’t take the risk,'” Monfil said. “I had retired in Wimbledon. I came back. I played this week. I had played a huge match. It was risky to play another match because I could risk hurting myself for real.”
WATCH: Shapovalov workshop inspires new generation of players
The 32-year-old Frenchman lost to Novak Djokovic in the 2016 Rogers Cup semifinals in Toronto. He improved to 4-1 all-time against Bautista Agut, with his only loss coming in the third round here in 2017.
This year’s women’s tournament, where Bianca Andreescu of Mississauga, Ont., advanced to the final, is being played in Toronto.
Fans braving the rainy conditions in Montreal watched part of the Canadian teenager’s victory over Sofia Kenin of the United States in the semis on the big screens at IGA Stadium.
The world’s No. 2-ranked player, Nadal won his fourth Rogers Cup last year in Toronto.
The top seed in Montreal with Djokovic and Roger Federer skipping this year’s event, Nadal battled back from an early deficit to down No. 11 Fabio Fognini of Italy 2-6, 6-1, 6-2 on Friday to advance.