Ian Thorpe could still emulate the 1972 Munich Olympics seven gold medal haul of Mark Spitz, former Australia head swimming coach Don Talbot said on Thursday.
Thorpe has been under intense scrutiny to reproduce Spitz's feat since he won three golds at the Sydney Olympics in 2000 and a record six titles at the 2001 Fukuoka World championships.
"Spitz, with all his winnings, is probably the number one right now," Talbot told reporters in Sydney. "He was a really great athlete but Ian is knocking on his door.
"Ian's only done one Olympics. I've great faith in him. The potential is there and I've never seen a better swimmer."
Thorpe, 20, won the Olympic 400 metres title and two relay golds as a 17-year-old at Sydney before winning a record six titles at the 2001 Fukuoka world championships.
Since then, Thorpe has added events like the 100 backstroke at the Manchester Commonwealth Games in 2002 and 200 individual medley at the Barcelona world championships last month to his programme, but has refused to say whether he will attempt to equal Spitz's performance at the 2004 Athens Olympics.
At Barcelona, Thorpe won the 200 and 400 metres freestyle, retaining his 400 crown to become the first swimmer to win a world title in the same event three times but was overshadowed by American teenager Michael Phelps, who set five world records.
Talbot also said Thorpe would need to win the 400 at Athens and Beijing in 2008 to be compared with Australia's Dawn Fraser, who won the 100 freestyle at the 1956, 1960 and 1964 Games.
"Dawn Fraser is so great in this country because she won over three Olympics. That has given her immortality as an athlete and swimmer," said Talbot, who was launching his book "Nothing but the best".
Talbot stepped down after Australia won 13 golds at the 2001 World championships.