Team Europe beat Team World 15-9 to win the inaugural Laver Cup in Prague.
Europe began the final day with a 9-3 lead, but, after a win apiece in the opening two matches on Sunday, John Isner beat Rafael Nadal 7-5 7-6 (7-1) to cut the advantage to 12-9.
Roger Federer then went to a match tie-break with Nick Kyrgios, who had a chance to force a deciding doubles.
However, Federer saved match point and won 4-6 7-6 (8-6) 11-9 to spark jubilant celebrations.
The competition, which follows a similar format to the Ryder Cup, saw Federer and Nadal play doubles together for the first time on Saturday.
There was one point awarded for victories on day one, two for wins on day two and three for victories on the final day.
Bjorn Borg (right) captained Team Europe while John McEnroe took charge of Team World
"It has been such an amazing and fun week and I'm so pleased the event has worked as it has," Federer, 36, said.
"The camaraderie in the group was amazing and we are all so happy. Time will tell how big the Laver Cup will become."
Dramatic to the end, the inaugural Laver Cup came down to the last – and arguably best – of the competition’s dozen matches as Roger Federer fought back to beat Nick Kyrgios 4-6 7-6(6) 11-9 and secure the first title for Team Europe.
The O2 Arena was a wall of noise as the most compelling singles showdown of the weekend delivered a high-wire act of a match, Kyrgios coming within a point of dragging Team World from 9-3 down at the start of the final day into the winner-takes-all doubles decider.
In the end, however, Federer sealed the title in a match tiebreak – the sixth of the weekend, and 18th tiebreak in all – recovering from 8-5 down and saving a match point at 9-8 to secure Team Europe’s triumph.
Roger Federer starts the celebrations
“I was ready to go – I had to be,” said Federer, who ended up contributing three victories and seven points to the hosts’ 15-9 victory. “That’s what a team member does. The boys played fantastic all weekend, but we knew it could change very quickly on Sunday.
The Team World boys have been great, in the doubles especially, and we knew it was going to be tough. I was looking at getting ready for a doubles at the very end. I’m very pleased and relived that we did win the singles and got it done.”
The result might follow the form book, but a glance to the other end of the court as Federer and Team Europe celebrated spelt out just how close John McEnroe’s Team World side had pushed Borg’s boys in blue.
A tearful Kyrgios was consoled by the Team World bench led by Jack Sock after seeing his sterling effort come up just short against the 19-time major champion. Unity, commitment, brilliance from both sides – the final chapter of the first Laver Cup had it all.