The final event of Federer's playing career veered off the script as he and Rafael Nadal lost in doubles on Saturday (AEST), before Team Europe succumbed to a 13-8 defeat in London.

Stunning singles wins for Felix Auger-Aliassime and Frances Tiafoe, against Novak Djokovic and Stefanos Tsitsipas respectively, followed a doubles thriller that saw Auger-Aliassime and Jack Sock topple Andy Murray and Matteo Berrettini.

After Team Europe won the first four editions of the Laver Cup, this time it has had to swallow the bitter pill of defeat, with Federer sorry to sign off on a losing note.

"Of course I'm disappointed," he said. "I was on the team. I almost lost my voice. My hands hurt from clapping.

"So, yes, I am disappointed. We wish the result would be different. I told Andy [Murray] in the locker room, I don't like losing. It's not fun. It just leaves not the best taste, you know. I think once you have been there and taste success, it's just not the same."

He said his goodbye tournament had been a mix of highs and lows.

"This weekend has been all over the place for me," said the 41-year-old Swiss. "I enjoyed it, but it's unfortunate that we couldn't get the win tonight."

Federer denied he has his eyes set on becoming the next Team Europe captain. Incumbent skipper Bjorn Borg and Team World counterpart John McEnroe have indicated next year's match could be the last that they helm, which would create an appealing vacancy.

"No plans there. Bjorn's doing a great job," said Federer. "Who knows, maybe one day, but we don't have any plans so far."

Next year's match takes place in Vancouver, and Federer will certainly have a role of some sort to play, given he is a co-founder of the event.

"I went through all different types of Laver Cups so far: the first one, the winning teams, now this time on the losing team," Federer said. "There was also one where I was hurt last year but seeing it more from the stands and from the fans' perspective, and now deep on the inside with retirement.

"I have enjoyed the Laver Cup in many different ways, and next year again will be totally different. I'm looking forward to it, and I'm sure Vancouver is going to be fantastic."

Asked what he would miss about tennis, Federer said: "Not the losing press conferences, I tell you that. They are the worst."