Federer has won 20 Grand Slam titles throughout his career and is closing in on Jimmy Connors’ record of 109 ATP tournament wins.
The Swiss star brought up his century with success in Dubai a fortnight ago.
But Nadal in closing in on the 37-year-old’s major tournament wins, sitting just three behind.
World No 1 Novak Djokovic has just five fewer Grand Slam titles than Federer.
But Toni Nadal, former coach and uncle to Rafael, thinks he knows why the pair continue to dominate.
“Nadal, [Andy] Murray, Federer, Djokovic and some others, like David Ferrer, were people very involved in their job and with an enormous ability to make sacrifices,” Toni Nadal told Mundo Deportivo.
“For Federer, despite his age and all that he won, the tennis keeps being a priority.
“The same happens with Rafa, despite all his injuries.
“You always had very good players, but this generation may have been more committed.
“If we look, Nadal, Djokovic and Federer won 52 Grand Slam titles combined.
“If we take as an example the generation of [Jimmy] Connors, [Bjorn] Borg and [John] McEnroe, which was very brilliant too, they won just 26.”
Federer is in Indian Wells Masters action tonight against Stan Wawrinka.
“First of all very happy that Stan is back,” Federer said ahead of the clash.
“He had more difficult knee surgery than I had, we both are happy that we still can play, expect a tough match against him.
“I think we will see a great Stan here, down the road, without a doubt, because I know what he can do.
“I think a lot of Stan. He’s got all the different options how to win points. He’s a fighter and a winner.
“I hope he’s going to be in the top 20, top 10 again very soon.”