The Swiss ace saved match point in the second set before winning the third set 11-9 in a super tie-breaker to clinch victory for Team Europe in the inaugural Laver Cup held in Prague last weekend (22-24 September).
Federer lost the first set 6-4 to the Australian and was then down match point in the second set tie break before mounting a comeback and winning in three sets. It was in between the first and second set that Nadal was seen chatting with his long-time rival, and when asked afterwards about their discussion, the Spaniard revealed that it was just a bit of advice with regards to Federer's forehand.
"Just to be a bit more aggressive," Nadal said when asked about his advice to Federer, as quoted by the Metro. "He was playing great, and controlling the points from the base line."
"But we thought that he could be a bit more aggressive on the forehand and Roger agreed," the 16-time men's singles Grand Slam champion added.
Meanwhile, Nadal and Federer have ruled out playing doubles together in the future after pairing up successfully for the very first time in their careers during the Laver Cup. The duo played on the same side of the court for the first time when they defeated Team World pairing Jack Sock and Sam Querrey.
The Swiss ace initially joked that one of them could change their nationality in order to play together at the Olympics, but when pushed on a serious note if they could consider playing doubles once their singles careers were done, both responded in the negative.
"No, that won't happen. Not from my side," Federer said, as quoted by the Metro.
"I don't think it's going to be a good idea," the Spaniard added. "I think we are singles players at the end of the day, so it's tough to imagine that way we keep playing doubles after we stop playing singles, no."