There was none of that sort of sadness Wednesday, just smiles and some chuckles at his own jokes, as Federer appeared at a news conference to discuss his retirement from professional tennis at age 41 after a series of knee operations.

He will close his career with a doubles match at the Laver Cup on Friday — perhaps alongside long-time rival Rafael Nadal. Federer said he is now at peace with the decision to walk away, which comes a few weeks after Serena Williams played what is expected to be her last match at the US Open, and he wants this farewell to be a celebration.

?“I really don't want it to be a funeral,” Federer said. “I want it to be really happy and powerful and party mode.” Wearing a blue blazer with the sleeves rolled up to his elbows and a white polo shirt, Federer took questions for about a half-hour at the arena that will host the team competition founded by his management company.

“I'm nervous going in, because I haven't played in so long,” he said. “I hope I can be somewhat competitive.” Federer, who announced last week via social media that he would be retiring after the Laver Cup, said it took him a bit to get used to the idea of stepping away from competition.

But it was something he understood he needed to do after running into setbacks in July during his rehabilitation from what was his third surgery on his right knee in about 1 1/2 years.

?“You try to go to the next level in training, and I could feel it was getting difficult. ... Then, I guess, I was also getting more tired, because you have to put more effort into it to be able to sort of believe that it was going to turn around. You start getting too pessimistic. Then I also got a scan back, which wasn't what I wanted it to be," Federer explained.

“At some point, you sit down and go, OK, we are at an intersection here, at a crossroad, and you have to take a turn. Which way is it?' I was not willing to go into the direction of: 'Let's risk it all.' I'm not ready for that. I always said that was never my goal.”

And the hardest part came when he knew he needed to stop. “You're sad,” Federer said, “in the very moment when you realize, OK, this is the end.'”

The last procedure on his knee came shortly after a quarterfinal loss to Hubert Hurkacz at Wimbledon in July 2021, which will go into the books as the last singles match of a superlative career that began in the 1990s and included 103 tournament titles, a Davis Cup championship for Switzerland, Olympic medals and hundreds of weeks at No. 1 in the ATP rankings.

In his online farewell message last week, Federer referred to retirement as a “bittersweet decision.” He was asked Wednesday what aspect was most bitter and what was most sweet. “The bitterness: You always want to play forever," he said.

“I love being out on court. I love playing against the guys. I love traveling. ... It was all perfect. I love my career from every angle.” And then he added: “The sweet part was that I know everybody has to do it at one point; everybody has to leave the game. It's been a great, great journey. For that, I'm really grateful.”

He will play doubles for Team Europe against Team World on Day 1 of the event, then will give way to 2021 Wimbledon runner-up Matteo Berrettini for singles over the weekend. That plan was run by the ATP and both team captains, John McEnroe and Bjorn Borg, Federer said.

As for his doubles partner for the last hurrah? Federer would not say definitively — he said that's up to Borg — but the not-so-hidden secret is that it is expected to be Nadal, who holds the men's record of 22 major championships.

Back in February, when word emerged that Federer would be in London this week, he said Nadal messaged him last year suggesting they play doubles together again. They teamed up to win a doubles match during the first Laver Cup in 2017.

“If we're able to possibly share the court one more time as a doubles pairing,” Nadal said in February, “then this would be a truly special experience for us both at this stage in our careers.”

While other contemporaries of Federer and stars of the sport are on Team Europe, such as 21-time Slam champ Novak Djokovic and three-time major winner Andy Murray, the Federer vs. Nadal matchup will go down in history as among the greatest rivalries in tennis or any other sport.

They played each other 40 times in all (Nadal won 26), with 14 Grand Slam matchups (Nadal won 10). Nadal came out on top in their classic 2008 Wimbledon final, considered by some the greatest match in history; Federer won their last showdown, in the 2019 semifinals at the All England Club.

“It could be quite, I don't know, a unique situation, if it were to happen,” Federer said about the doubles pairing. “For us, as well, to go through a career that we both have had and to come out on the other side and being able to have a nice relationship, I think, is maybe a great message, as well, to not just tennis but sports and maybe even beyond."

As for his future? The father of two sets of twins — girls 13, boys 8 — wouldn't say exactly what he has planned, other than a vacation, but he did say he would remain connected to tennis in some capacity.

Recalling the way Borg stayed away from the sport for years after retiring, Federer sought to reassure his own fans by saying: “I won't be a ghost.”