Top-ranked Novak Djokovic survived two match points and rallied to beat Latvia's Ernests Gulbis 5-7 7-6 (9/7) 6-1 on Friday night in the Rogers Cup quarter-finals.
It was the first time Djokovic survived match points against him since 2012 in Shanghai against Andy Murray.
The Serb, the tournament champion in 2007, 2011 and 2012, has won 51 of 54 matches this year.
"You have to give credit to (Gulbis) for playing an excellent match," Djokovic said.
"He was always making me play an extra shot, and putting a lot of pressure on my second serve.
"I had a lot of chances and closed it out in the end, but he had a couple of match points and it would've been deserved if he had won this match."
Djokovic will face France's Jeremy Chardy, a 6-7 (11/9) 7-6 (15/13) 7-6 (7/4) winner over American John Isner in the rain-delayed opening match.
Fourth-ranked Kei Nishikori of Japan beat fourth-seeded Spanish star Rafael Nadal of Spain 6-2 6-4.
The tournament winner last week in Washington, Nishikori topped Nadal for the first time in eight attempts.
"It took a long time to beat Rafa," Nishikori said. "I don't usually like to play against him, but the last couple of matches - I had chances in Australia and in Madrid last year - so I knew I was close."
Nishikori was all over Nadal's serve, breaking twice in the first set and twice more in the second.
"Today, I was almost dominating everything, so I'm very happy," Nishikori said.
Nishikori will face the second-seeded Murray. The Scot beat 10th-seeded defending champion Jo-Wilfried Tsonga of France 6-4 6-4.
