Nadal says mental strength has returned

Rafa Nadal says his mental stability has returned after a topsy-turvy year for the former world number one.

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.

"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.

"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.

World number one Novak Djokovic is the top seed.

Nadal in 2015:

Matches: 51
Wins:      39
Titles:     3