Eight-time grand slam champion Andre Agassi has picked Spaniard Rafa Nadal over Swiss maestro Roger Federer as the greatest tennis player ever, according to a newspaper report today.

The 32-year-old Federer, with 17 grand slam titles, leads his younger opponent who has 13 majors and is recognized as a complete player on all surfaces.

"I'd put Nadal No. 1, Federer No. 2," Agassi told Singapore's Straits Times newspaper, stoking the popular debate.

Nadal leads Federer 23-10 in all meetings and Agassi said the number of grand slam titles cannot be the sole yardstick to decide the greatest player.

Agassi said "It's just remarkable to me what he has done, and he has done it all during Federer's prime."