(CNN) When will Roger Federer retire? It is a question that tennis' all-time great has been asked in recent years, especially after he suffered a freak knee injury in 2016 and moved into his mid and now late 30s.

But all those Federer fans out there -- and there are plenty of them given the Swiss boasts a combined 17.7 million followers on Twitter and Instagram -- can relax.

In an interview with CNN Sport's Christina Macfarlane, Federer didn't sound like he would be stopping in 2019 -- which marks his 21st year as a pro.

He's feeling confident ahead of his title defense at the Australian Open that begins next week.

Far from being weighed down by two decades on tour, the 20-time grand slam winner continues to love the game and traveling the world with wife Mirka and their two sets of twins.

JUST WATCHED Tearful Roger Federer remembers late coach Replay More Videos ... MUST WATCH Tearful Roger Federer remembers late coach 03:21

"I see these most amazing ... get to meet crazy, cool people, amazing fans, support I have around the world," he said. "I get to experience this life that is just really surreal.

"I don't know what it is, if it's geometry of the flight of the ball, or what a drop shot can do with the spins, and being with my team and trying to still be better at 37.

"All these things are really exciting to me. It's a mixture of everything why I'm still playing tennis today."

JUST WATCHED Federer hoping to claim his 100th career title Replay More Videos ... MUST WATCH Federer hoping to claim his 100th career title 03:56

'Wimbledon stands out'

When he does eventually call time on his career, though, Federer unsurprisingly said that Wimbledon might be the ideal place for a farewell tournament.

After all, no man has won more than Federer's eight Wimbledon titles, including five in a row from 2003-2007.

"I have a lot of places that are very special to me, thankfully. I've been very fortunate. But yeah, sure, like a Wimbledon stands out as maybe a place, but there are actually also many others," said Federer.

"I've been thinking about it, like where is that place?"

JUST WATCHED Federer: 'Dream scenario' to win 8th Wimbledon Replay More Videos ... MUST WATCH Federer: 'Dream scenario' to win 8th Wimbledon 02:41

Surely Basel would be in the mix, too. Federer served as a ball boy at his hometown event before going on to hoist the trophy nine times.

"But I think it will all come down to, is it the body, is it the family, is it the mind, is it one morning when I wake up, how does it happen?" added Federer.

"And then maybe that day that it happens, maybe that is the end, or maybe I say I can maybe get a few more tournaments left in me, I don't know.

"And then maybe that one tournament I think that it could be is way too far away, and then you just can't make it there."

But he insists: "It should be a happy, celebration day, not a sad funeral-type day. I hope it's not like that for me."

His legions of supporters held their collective breath two years ago, hoping it wouldn't be the end for Federer.

He underwent surgery for the first time in his career early in 2016 after hurting his left knee while running a bath for his twin daughters in the aftermath of a semifinal defeat to Novak Djokovic at the Australian Open.

Worse was to come -- at Wimbledon. Leading Milos Raonic by two sets to one in the semifinals, Federer lost in five sets, reinjured the knee and decided to sit out the final six months of the campaign.

But in what was a remarkable comeback, Federer won the first grand slam of his return. He grinded out three five-set wins at the Australian Open in January 2017 and ended a 10-year losing streak at majors to his greatest rival, Rafael Nadal.

JUST WATCHED Roger Federer on his first Wimbledon title in 2003 Replay More Videos ... MUST WATCH Roger Federer on his first Wimbledon title in 2003 01:09

On his terms

"I hope it doesn't end with an injury," Federer said. "I'd like to go out on my terms.

"I don't have the fairytale ending in my head saying there has to be another title somewhere, and then I have to announce it big and say, that was it, by the way, guys. I don't have to have it that way.

"If I wanted it that way, I could've maybe said it after the Australian Open when I beat Rafa in that epic final. I don't know if it's ever going to get better than that, because that was it for me."

Amid the uncertainty about when his career will eventually include, one thing Federer won't do, he said, is announce a farewell season. He was advised against it by his former coach and one of his boyhood idols, Stefan Edberg.

The six-time major winner, a stylish serve and volleyer, did it in 1996.

"It was something unusual and I would not suggest it to anyone because it created an extra pressure," the Swede was quoted as saying by Tennis World USA in June.

Based on his 2018 season, no one will say Federer should hang up his rackets anytime soon.

A five-set victory against Marin Cilic in Melbourne lifted his tally of grand slams to 20 and Federer ended the season ranked third in the world.

JUST WATCHED Federer: Six-month layoff was right decision Replay More Videos ... MUST WATCH Federer: Six-month layoff was right decision 02:30

There were some bumps thereafter, such as exiting in the quarterfinals at Wimbledon after holding a two-set lead and match point against Kevin Anderson and succumbing to John Millman -- and the humid conditions -- in the fourth round of the US Open.

But in November at the Paris Masters, he stretched Laver Cup teammate Djokovic -- back to being the player to beat in men's tennis -- to a long three sets.

Feeling confident

JUST WATCHED Australian Open 2017: the best ever? Replay More Videos ... MUST WATCH Australian Open 2017: the best ever? 02:13

If Federer makes it three in a row Down Under he would land his 100th title overall and his biggest one since signing with clothing sponsor Uniqlo last year in a deal reportedly worth $300 million.

"I feel good," said Federer. "I've been training really well. I've had another great season (in 2018). I'm still happy playing, and I won the last two Australian Open editions. So yeah, I definitely should be going in there with confidence.

"I love playing in Australia, love playing in Melbourne. There's so much that connects me to the place, the legends that I admire from that country, the coaches that I've had," he added, mentioning Peter Carter and Tony Roche.

"I'm very excited that it's around the corner."