Rafael Nadal remained on course for a record 31st Masters title after beating Grigor Dimitrov 6-4, 6-1 in the Monte Carlo semifinals on Saturday.
Nadal shares the Masters record with Novak Djokovic, whose 30 wins include two here.
The top-ranked Nadal will face Kei Nishikori, who beat No. 4-ranked Alexander Zverev 3-6, 6-3, 6-4.
Nishikori won on his first match point when Zverev scooped a backhand wide. The German player looked jaded, having finished a long and grueling quarterfinal at 9 p.m. on Friday.
Nishikori has never won a Masters and last reached a final two years ago in Montreal. He trails 9-2 against Nadal in head-to-heads. Nishikori won their last encounter two years ago to take the bronze medal at the Olympic Games in Rio de Janeiro.
Nadal never looked in trouble as he beat No. 5 Dimitrov for the 11th time in 12 career meetings.
"In the second set, he started to miss more," Nadal said modestly. "I was there solid. That's all."
If Nadal wins Sunday's final, he will earn a 76th career title and keep his No. 1 ranking. Should he lose, Roger Federer will reclaim the top spot.
"Being in 12 finals already here is something difficult to imagine," said Nadal, who has lost only one, to Djokovic in 2013.
Dimitrov came out firing, but he was mostly more miss than hit.
The Bulgarian pressured Nadal with two superb lobs, forcing a backhand smash wide from the Spaniard for deuce. But Nadal held a tight first game lasting eight minutes, and then broke Dimitrov for 2-0.
Dimitrov found his range, broke Nadal back and held for 3-3. The next two games were even, with Dimitrov matching Nadal in the rallies.
Dimitrov cracked trying to serve for 5-5. He made consecutive double faults and hit a wild forehand long to trail 15-40. He saved one set point but Nadal was in ruthless mode and took the next chance.
Two consecutive love breaks and three easy holds made it 5-0 to Nadal in the second set.
"You see me with a smile. I'm a positive person," Dimitrov said. "Deep down, I'm hurt. I hate losing. Simple as that."