The 29-year-old Spaniard arrived in Canada last week for the start of the North American hardcourt swing having picked up his third title of the year in Hamburg.
He will now hope to build on that as he attempts to claim a fourth Rogers Cup title.
"It's always about adapting your tennis," Nadal, beaten by lowly-ranked Dustin Brown in the second round at Wimbledon, told the ATP's website about the challengers in store over the next few weeks leading up to the U.S. Open.
Marion Bartoli: Rafa Nadal no longer in ‘Big Four’
14/07/2015 AT 14:16
[ANALYSIS: Are Rafa Nadal's glory days gone forever?]
"There's a different way of hitting the ball, but at the end of the day it's tennis. Hamburg had been a positive week for me.
"Mentally I was stable all week, something that I wasn't able to do very often this season.
[OPINION: Marion Bartoli: Rafa Nadal no longer in ‘Big Four’]
"My mental powers have been up and down more. Hamburg was not the case and I'm working well."
Twice U.S. Open champion Nadal, seeded seven, faces a potential quarter-final in Montreal with world number four Kei Nishikori who opened his hardcourt season with the title in Washington at the weekend.

Rafael Nadal is dumped out of Wimbledon by world number 102 Dustin Brown

Image credit: Imago

Is this a bit of sports psychology, or a genuine declaration of intent? It's impossible to say right now. Even in his few bright points earlier this season Nadal was generally cagey about predicting a return to the top, however, so we're inclined to believe that there might be genuine belief in these words, following his win in Hamburg recently.
At his peaks in 2015 - admittedly a rare sight - Nadal has looked physically and technically excellent, but his inability to sustain that level has been borderline shocking at times, particularly in the string of defeats that saw him lose his French Open crown and bow out early at Wimbledon.
So if it's true that he has his mental strength back? Well, that's pretty much all he was missing. Let's hope it proves so, at least, because tennis has been poorer this season for his absence from the top table.
Are Rafa Nadal's glory days gone forever?
03/07/2015 AT 07:54
Murray will not be 'wading in' with advice for Raducanu