Rafael Nadal heaped praise over Roger Federer after he was displaced as the world No.1 by the Swiss earlier this week.

By beating Robin Haase in the Rotterdam Open quarter-finals two days ago, Federer climbed to the top of the ATP ranking once again in his brilliant career.

He also broke some impressive records by doing it.

"The Maestro" became the oldest player on the men’s tour to become the World No.1 at 36 years of age, surpassing the existing record (Andre Agassi, at 33).

Federer also beats the mark set by the record holder in the women's ranking Serena Williams, who was 35 when she was last No.1 in May 2017.

Federer also claims the men’s record for biggest gap between spells at No.1, as it has been five years and 106 days since he was on top of the ATP ranking on November 4, 2012.

Federer can extend his lead over former No.1 Nadal if he beats Grigor Dimitrov in the final of the tournament in Rotterdam later today.

It has been an amazing journey back to the top for Federer.

For the last 13 months, since he made a return from an injury, he has won three out of five Grand Slams.

And, Nadal was full of praise for his rival for proving once again the magnitude of his greatness.

“Roger Federer has amply demonstrated what he is and did not need to return to No 1 to prove it,” Nadal told Spanish radio Carrusel.

“At his age he has achieved something very complicated and we must congratulate him.”

The moment when these two will no longer bless us with their rivalry on the court will come one day, but the Spaniard insists that he hopes him and Federer will have more battles to come in the future.

“Federer and I do what we can and there will come a day that we won’t be able to,” Nadal admitted.

“In the meantime, welcome, we’ll give the most and see how long it lasts.”

Roger Federer will face Grigor Dimitrov (Bul) later today, seeking for his third ATP Rotterdam trophy.