Spitz backs Phelps to win 'several' golds

US swimming great Mark Spitz on Friday backed Michael Phelps to set the Rio Olympics alight and win "several" gold medals in what is likely to be his Olympic swansong.

Spitz, whose record of seven gold medals at a single Olympics was broken by Phelps' eight in 2008, said he expected the 31-year-old to make light of his advancing age in the Rio de Janeiro pool.

"I think so. Several," Spitz told AFP in Rio, when asked if he thought Phelps would win gold medals at this Olympics.

Phelps won the 100m and 200m butterfly and 200m medley at last month's US trials, but not with the sort of sizzling times that would make the rest of the world sit up and take notice.

But Spitz said Phelps was not properly rested for the trials, and said the extra incentive of swimming his final Games ensured that the record 22-time Olympic medallist would remain a force to be reckoned with.

"I think Michael is going to do great," said the 66-year-old, who was meeting US athletes at their picturesque training base on the Rio coast.

"I think that he was not fully rested at the Olympic trial, I think that this is his swan song if you may and he's going to make every single stroke count.

"I would never bet against him and I hope that he'll have a positive result. If he makes the finals, he's the one to beat."

While Phelps' feats mean he's never out of the spotlight, Katie Ledecky may be the big star of the US team which is expected to dominate the pool once again.

"I think we're going to do really well," said Spitz.

"The women are going to do well with Katie Ledecky, everybody's got their hopes pinned on that she'll win the 200, 400 and 800 free.

"She's got the fastest times in the world right now and she's the person to beat. She's going to set the standard right now for the women's swimming.

"But there's a lot of great swimmers coming from South Africa, Germany, Japan, Australia."

Spitz's phenomenal haul of seven gold medals at the Munich 1972 Olympics was considered unbeatable until Phelps came along 36 years later.

But Spitz said he had never fully appreciated the size of his own achievement until Phelps went one better in the Beijing Water Cube.

"Somebody asked me the other day, 'When did you realise you were so great?' I said, 'The day Michael Phelps broke my record,'" Spitz said in an address to the US athletes.