A tearful Roger Federer waved goodbye to professional tennis after teaming up with fellow great Rafael Nadal on an emotional night at the Laver Cup.

The Swiss, who won 20 Grand Slam singles titles, is considered one of the best players in tennis history.

"It's been a wonderful day. I'm happy, not sad. It feels great to be here. I'm happy I made it through," he said.

Federer cried as he hugged Nadal and other players, then took acclaim from the thousands of fans who chanted his name at the O2 Arena in London.

Nadal also could not hold back the tears. The 36-year-old Spaniard cried as he sat alongside Federer while the pair listened to British singer Ellie Goulding, who rounded off a memorable night with a performance.

Federer and Nadal - for so long rivals at the top of the men's game - joined forces to play doubles against American pair Jack Sock and Frances Tiafoe in the annual team event between Europe and the rest of the world.

Despite Federer not having played competitively for over a year, the veteran duo pushed Sock and Tiafoe before losing 4-6 7-6 (7-2) 11-9 as Team World levelled at 2-2 at the end of play on the opening day.

Federer and Nadal - affectionately nicknamed 'Fedal' - almost won it. The pair had a match point at 9-8 in the decider, but Federer could only lunge for a forehand which he pushed into the net.

The defeat brought the former world number one's 25-year professional career to a close after his 1,750th competitive match across singles and doubles.

"It's been the perfect journey. I'd do it all again," said Federer as tried to hold back tears during his on-court speech.

Federer throws the retirement celebration he wanted

Federer's career had long been on the downward slope, having battled a knee injury for the past two years and needing three operations in a bid to overcome the problem.

He had not played a competitive match since losing to Poland's Hubert Hurkacz in the quarter-finals at Wimbledon last year.

Despite being restricted to only three of the 11 Grand Slams staged since the start of 2020, he hoped as recently as July he would still be able to return to the major tournaments.

But, after a scan brought further bad news, Federer announced last week he was going to retire because his "body's message lately has been clear".

Federer had talked about throwing a party to mark his final match, saying he wanted the occasion to be fun and not funereal.

As he wished, there was a celebratory atmosphere in the 17,500-capacity arena.

Watched by his wife Mirka, their four children, plus his parents Robert and Lynette, Federer's every move was greeted with cheers containing a mixture of euphoria and empathy.

The family joined him on court afterwards during a poignant celebration, which saw many more tears and Federer hoisted aloft by his fellow players.

"Everyone's here, the boys and girls. My wife has been so supportive. She could have stopped me a long, long time ago but she didn't," said Federer.

"She kept me going and allowed me to play, so it's amazing - thank you."

The presence of several tennis legends including Rod Laver, along with celebrities including Hollywood actor Hugh Grant and Vogue editor Anna Wintour, added to the occasion.

Current world number ones, Carlos Alcaraz and Iga Swiatek, tweeted their range of emotions as they watched the match on the television, as did Federer's Swiss Davis Cup team-mate Stan Wawrinka.