Roger Federer admits to have surprised himself by the speed of his recovery from knee surgery he underwent last year. The Swiss number one went under the knife in March 2016 and then withdrew from the second half of the season after falling on his knee during his Wimbledon loss to Milos Raonic.

But since returning, Federer has instantly recaptured his best form taking his tally of grand slams to 19 with wins at the Australian Open and then at Wimbledon, where he became champion for a record eighth time. Such has been his form, which also saw him claim two Masters 1000 titles at the start of the year, he is honing in on returning to world number one.

Significant progress at the Rogers Cup in Montreal - where his campaign began with a straight sets win over Peter Polansky in just 53 minutes - and then at the Cincinnati Masters next week will see him return to the top of the ATP rankings before the US Open later this month. The achievement would be represent a remarkable turnaround from a year ago when Federer announced he would miss the remainder of the season and threw his future in the sport into major doubt.

"Honestly, when I went into surgery, I was rather sad last year," Federer admitted to reporters following his second round win. "I was rather worried about how I was going to come out of it. When I did come out of it, I was happy I woke up again. I was sad that I had an operated knee. It was actually quite emotional for me. I was scared, as well, at the same time just to be in pain, of the unknown, I guess. I was not thinking of having a start to this kind of a season like back in 2006.

"The key is that I'm actually healthy. I knew that when I was healthy, I was going to be able to have chances to win slams again, to play against the best, beat the best. That's also the reason why I'm still playing today. If I felt like I couldn't do all these things, it would not be enjoyable or I wouldn't be doing it any more. I would accept it, say, Look, I had a great career, but thanks very much, I'll do something else."

Rafael Nadal can go to world number one for the first time in over three years if he reaches the semi-finals in Canada, but Federer's return to the summit of the men's game, a position he has not occupied since November 2012, is imminent. Pursuit of a return to the ATP rankings summit was triggered by the decision to play in Monreal this week following a complete break from the sport.

"I didn't practice very much between Wimbledon and here," he added. "It was 10 days off, five or six days of fitness, it was a bit of tennis. That's when I decided to come here. I practiced here for another couple of days, and here I am.

"I'm not that well-prepared as such, but I am fresh and I'm ready to go and I'm eager to do well. That can always lead to good things. As in a game plan right now, it's pretty straightforward, you know, trying to play on my terms. Conditions are fast. We'll see how it goes."

Roger Federer
Federer is eyeing a return to world number one before the US Open. Getty Images