Nadal congratulates Federer after losing No. 1 spot to him

Rafael Nadal has praised his arch-rival and good friend Roger Federer, who will take over the Spaniard as the world No. 1 when the latest rankings are released today.

Federer, 36, ensured that he will be the oldest player to reach the top spot after beating Robin Haase in the Rotterdam Open quarter-finals on Saturday morning (Singapore time).

The 20-time Grand Slam champion went on to defeat Andreas Seppi 6-3, 7-4 (7/3) in the semi-finals yesterday morning (Singapore time) to set up last night's final with Grigor Dimitrov.

"Roger Federer has amply demonstrated what it is and did not need to return to No. 1 to prove it," Nadal, 31, told Spanish radio station Carrusel.

"At his age, he has achieved something very complicated and we must congratulate him."

American Andre Agassi held the previous record as oldest world No. 1 on the ATP Tour when he topped the rankings at the age of 33 in September 2003.

After achieving the feat, Federer showed a sense of humour by tweeting: "Apparently I'm the oldest tennis player with a #1 ranking. Somebody might have mentioned that to me already, but I had a hard time hearing."

Jokes aside, Federer hinted he might play in the Dubai Open, which starts next Monday, demonstrating his hunger to compete.

Nadal added: "Federer and I do what we can and there will come a day that we won't be able to.

"In the meantime, welcome, we'll give the most and see how long it lasts."