To say that Roger Federer has come a long way in his career would perhaps be one of the biggest understatements in sport.

The journey began in his native Basel, where he played his first ATP event at the 1998 Swiss Open aged 16. His opponent was Argentina's Lucas Arnold Ker, who was runner-up at the French Open in men's doubles a year earlier.

Federer lost 6-4 6-4 in a mere 80 minutes with his conqueror far from impressed by his talent.

"Roger had a good serve, a good forehand... but his backhand was stunted, not good at all," Ker told the ATP Tour's website in 2020. "I remember moving him over there all the time and that allowed me to beat him solidly in two sets.

"I never thought or imagined that Federer was going to be one of the best in the world and in history, I really didn't."

Yet that is what Federer has done with his various accomplishments that have rewritten the record books on multiple occasions.

Over two decades he became the most-decorated male player of all time at Wimbledon by winning eight titles, spent a record 237 consecutive weeks as world No.1 and is the only player to have reached the final of every major event within the same year on three different occasions.

Federer's rise has not just benefited him, it helped promote tennis to a wider audience around the world. He was the player many young children aspired to be and the person who international brands want to be associated with.

Even now at the age of 41, he remains one of the most valuable athletes in the world with Forbes magazine estimating his annual earnings to be $90.7m (£80.6m), of which $90m (£80m) was generated from off-court earnings such as endorsements. According to the publication, there are just six athletes who have earned more than him.

"His impact on the game has been tremendous, the way he was playing, his style, effortless, just perfect for an eye of a tennis coach, player or just a tennis fan," long-time nemesis Novak Djokovic told reporters on Wednesday at London's Tower Bridge.

"He has left a huge legacy that will live for a very long time."

Throughout his career, Federer has said his success has been driven by rivalries with Djokovic and Rafael Nadal. Known collectively as the Big Three, they have largely dominated the landscape of men's tennis for years, winning 63 major events between them.

It is highly subjective as to which member of the trio should be given the greatest of all time (GOAT) award, but Federer has his own view about the debate.

"I am my own career, my own player, that needed those challenges. They needed a challenger like myself," he told the Associated Press.

"We made each other better. So at the end of the day, we'll all shake hands and be like, 'That was awesome.' Now is somebody going to be happier than the other? I mean, in moments, maybe."

Unfortunately for the Swiss tennis giant, even legends of the sport have their expiry date. For Federer, a persistent knee problem which has caused him trouble for months contributed to his decision to retire - a cruel sense of irony for somebody who has played 1,526 singles matches without retiring once.

"It was about time that I retired. I think a moment like this doesn't come overnight. It was a process – an emotional one – which at the end I thought we managed well, with the family, the team, my closest friends," Federer said on Wednesday at The O2 Arena.

"It all worked out and here we are now at the Laver Cup. But it was definitely more a highly unusual last few weeks for me."

The final stop in Federer's career will be on Friday in the Laver Cup where he will be representing Team Europe in a doubles match alongside Nadal, a player who made his Grand Slam debut at the same event where Federer won his first major title - the 2003 Wimbledon Championships.

Like Djokovic, Nadal has been a formidable rival of his with the two clashing on Tour 40 times between 2004-2019.

It is events like the Laver Cup where Federer's legacy will continue for years to come. His sports agency TEAM8 is one of the co-founders of the competition and he has vowed to continue his work with the event, ensuring that his association with the sport survives beyond his retirement.

"I feel tennis has given me too much. I have been around the game for too long. Have fallen in love with too many things. You'll see me again. In what capacity, I don't know. Still have to think about it a little bit, give myself some time."

For tennis fans, they can never see too much of the Swiss maestro, and almost universally loved artist who reached levels of near-perfection very rarely seen in any sport.

Roger Federer's career in numbers

Grand Slams

20 - Grand Slam titles
8 - Wimbledon titles
6 - Australian Open titles
5 - US Open titles
1 - French Open title
31 - Grand Slam finals
5 - Reached the final of each Grand Slam at least five times
3 - Reached the final of every Grand Slam in three different seasons
23 - Consecutive appearances in Grand Slam semi-finals from 2004 to 2010
36 - Consecutive appearances in Grand Slam quarter-finals
65 - Consecutive Grand Slam appearances from the Australian Open in 2000 to the
French Open in 2016
369 - Match wins in Grand Slams
22 - Consecutive appearances at Wimbledon

Overall

103 - Career titles, second in the Open Era behind Jimmy Connors
310 - Weeks spent at world No. 1
237 - Consecutive weeks at world No. 1
1,251 - Career matches won out of 1,526
£116,028,499 - Career prize money
65 - Consecutive matches won on grass from 2003 to 2008
12 - Titles won in 2006, his most successful season
92 - Matches won from 97 played in 2006