The duo paired up for a doubles clash in the recently concluded Laver Cup for Team Europe and came out victorious against Team World's Jack Sock and Sam Querrey.
Federer admitted that it was a learning experience playing alongside his long-time and arguably his greatest rival. The Swiss ace revealed that he got to see firsthand Nadal's decision making process, especially during the big moments of the game.
The duo, who have a combined 35 men's singles Grand Slam titles between them, looked to be in good spirits throughout the game and combined well despite having trained just once before. Federer revealed that they never practise together as they do not want to show each other their strengths and weaknesses – as in the last decade they have faced each other a number of times in the latter stages of tournaments.
"For me personally it was a great moment – we have only ever practised once together," Federer said, as quoted by the Metro. "It was back at the world tour finals."
"We don't practise a lot we don't show stuff to each other. We will always forever be rivals as long as we're active. This was something very special.
'It's been an absolute pleasure sharing the court with Rafa. Being on the same side of the net you know you can trust him in the big moments. Seeing his decision making and his thought process was very interesting," the 19-time men's singles Grand Slam champion explained.
Nadal was also delighted to share the court with Federer and admitted that it was a long-term dream to partner his rival in a tournament. The two veterans tasted victory not only in their match as Team Europe went on to win the inaugural Laver Cup.
"After all the history that we had behind us as rivals it was great to be on the same side of the court fighting for a team it was something we enjoyed a lot. The atmposhere for the whole match and during the weekend was fantastic," Nadal added.