Whenever Rafa Nadal and Roger Federer share the court, tennis fans are treated to a spectacle.
The two tennis legends have had some incredible battles at various tournaments when facing each other either side of the net.
And, last weekend, there were sharing the court once again.
However, this time, they were on the same side of the net as teammates.
Federer and Nadal - or ‘Fedal’ played for Team Europe against Team World during the continent's 15-9 Laver Cup victory.
Fedal took on Sam Querrey and Jack Sock on Saturday and triumphed 6-4 1-6 10-5.
After the match, Querrey admitted that the pair would definitely be contenders for four Grand Slams a year if they were to team up - a move that tennis fans would no doubt love.
But is that really a possibility when they get too old to play singles?
'Fedal' to reunite again?
Well, yes. But only if they switch nationality.
“Yeah, that’s a great idea,’ Federer said before turning to Nadal and saying: “Are you going to become Swiss, as well, maybe, and then we can play doubles together at the Olympics?
“Or I will become a Spaniard? I don’t know.”
But, in all seriousness, Federer didn’t think it was a possibility.
“No, that won’t happen. Not from my side.”
Watch: Federer responds to the future of 'Fedal'
Check out his answer:
Ah, such a shame.
Back to being rivals and Federer is chasing Nadal at the top of the ATP ranking.
The Swiss trails the Spaniard by almost 2000 points and has revealed his upcoming schedule after admitting catching Nadal is almost impossible this year.
"Now I have Laver Cup, Shanghai, Basel, Paris and London. That’s my schedule, and it won’t change," he said.
"Next weeks will be extremely important with Shanghai, Basel, maybe Paris and ATP Finals in London.
"My goal is to get to Shanghai early, maybe on Friday. Basel will take priority over Bercy.
"It [the year-end world No. 1 ranking] became a little bit secondary for me as Nadal got far away.
"I will focus on myself and I will play only when I am ready.
"Back was really doing bad after Montreal and there was a little problem after another. After the last match played in New York I felt really happy to take a break. Now I am doing well."