Alexander Zverev is heading into his first-round match at the National Bank Open off the back of 10 days working with Rafael Nadal's uncle, Toni, in Mallorca. And the German admits he is trying his hardest to extend their professional partnership as he looks to bounce back from a devastating trip to Wimbledon, where he fell at the first hurdle.

In the aftermath of his loss to Arthur Rinderknech, Zverev opened up on his struggles with the mental side of the sport and admitted that he would consider getting therapy. The 28-year-old is still coached by his father, Alexander senior, but he opted for a change of scenery after crashing out at the All England Club by linking up with 'uncle Toni', who coached Nadal for 27 years.

"After Wimbledon he contacted me," Zverev explained after landing in Toronto. "I was very grateful that he did. We talked on the phone for about an hour and a half, exchanged some messages and then decided to go to Mallorca to see him.

"He is a person who, in my opinion, is a great coach, without a doubt, but he is also someone who can give you a lot of confidence, because when he speaks and when Rafa speaks, you listen.

"Rafa gave me a great perspective on what it's really like to play against me. We spent hours and hours talking, sometimes even past midnight at some dinners and things like that."

The prospect of Nadal teaming up with Zverev on a full-time basis appears slim, however, because of the Spaniard's busy schedule.

"The stay in Mallorca was incredible," Zverev continued. "I spent about ten days there, worked very hard and also enjoyed it very much. I think Toni enjoyed it too. I am trying to convince him to spend more weeks with me, we will see how it goes, but he is a very busy man.

"He has many appointments that he has already committed to this year, so I'm not sure how much you will see him. But we are definitely talking about what a possible collaboration could look like."

After Zverev's Wimbledon disappointment, Boris Becker was one of the high-profile tennis voices who suggested that his compatriot should consider shaking up his coaching team. "His father and brother did an excellent job," said Becker. "But it wasn't good enough for the final step."