The 2018 champion powered past Guido Pella 6-36-4 on Thursday to book a place in the quarter-finals and duly recorded his 379th Masters 1000 win.
Nadal has a formidable record at the Rogers Cup with four title wins at the event.
"I'm having a good season more or less, being competitive nearly in every single event that I have been playing", he said.
"With all the traveling and short transition, two very tough matches yesterday and two days ago, I think the battery was empty today". "If I had the chance to have the legs that I had in that 2005, probably would be a very, very good player, no?"
Daniil Medvedev, of Russian Federation, reaches out for the ball in his match against Dominic Thiem, of Austria, during quarterfinal play at the Rogers Cup tennis tournament in Montreal, Friday, Aug. 9, 2019.
Thiem, who before this week had never won a match in five attempts in Canada, had his hands full against 14th-seeded Cilic but did well to save all nine break points he faced while relying on a steady stream of groundstroke winners. "But I just tried to give him a quote about how I went through that process that he's having", the Spaniard further added. But we are used to playing like this.
"Of course, I had some physical issues the first three, four months of the season".
Nadal broke Fognini, 32, again to open the third set, and the Italian requested a medical timeout during a changeover down 3-1 to get his right foot/ankle tapped.
Up next for Thiem will be Russian eighth seed Daniil Medvedev, a 6-3, 6-3 victor over Chile's Cristian Garin.
The night session concludes with a battle of veterans when No. 10 seed Roberto Bautista Agut of Spain squares off with No. 16 seed Gael Monfils of France.
Thiem and Zverev, the second and third seeds respectively, bowed out with straight-sets losses.
Khachanov secured the all-countryman semi by dispatching a lackluster Alexander Zverev 6-3, 6-3.
"He's having a great season already winning a Masters 1000 and playing some great matches all around".