FOR many Roger Federer may be the greatest tennis player of all time.

But even he would agree that Michael Phelps ranks above him in some ways.

And, rightfully, he paid tribute to the greatest Olympian of all time.

Federer said he appreciated the effort and sacrifices which have gone into the 23-year-old's march to a record 11 Olympic gold medals, more than any other athlete in history.

'What he's doing is quite incredible. He's been doing it for so many years,' said Federer, who is seeking a first Olympic tennis gold here and is desperately chasing down his own piece of history - Pete Sampras' record of 14 Grand Slam titles.

'He's doing it in different competitions at different lengths. He's very impressive and he's one of the greatest athletes out there at the moment.'

Phelps started yesterday with a career nine Olympic golds to stand alongside greats Paavo Nurmi, Carl Lewis, Mark Spitz and Larysa Latynina.

But the man from Baltimore clinched his place in the history books when he won the 200m butterfly in a world record time of 1min 52.03sec, shaving six-hundredths of a second off the world mark of 1:52.09 he set in winning the world title in Melbourne last year.

VICTORY

An hour later he returned to lead the United States to victory in the 4x200m freestyle relay in 6:58.56 - crushing the previous world mark of 7:03.24 set by a

US squad at the World Championships in Melbourne last year.

He has now won five gold medals in Beijing's Water Cube, to go with the six he collected in Athens four years ago.

If Phelps can win all eight of his Beijing events, he will surpass the record of seven gold medals at one Games set by US swimmer Spitz in Munich in 1972.

His fellow countrymen were dazzled by his achievements.

'He's one of the greatest swimmers of all time,' said Dwayne Wade, part of the US' powerful men's basketball squad in Beijing.

Some Olympic competitors admit they are in awe of Phelps. 'I had dinner with Michael Phelps (at the Athletes Village),' said Australian basketball player Patrick Mills. 'But I was too shy to talk to him.'

Phelps, himself, is keen to keep his feet on the ground and said he was stunned to see NBA superstars Kobe Bryant and LeBron James up in the stands cheering him on into history.

'It's pretty cool seeing athletes of their calibre supporting you,' said Phelps. 'I heard that they were even responsible for starting some of the chants.' - AFP.