AMERICAIN has replaced Dunaden as Melbourne Cup favourite - thanks to the Ollie factor.

Since the Herald Sun revealed on Saturday that Damien Oliver had replaced controversial Frenchman Gerald Mosse on Americain, the French stayer has been strongly backed to repeat his 2010 Cup triumph.

In 48 hours Americain has firmed from $9 to $5.50 outright favouritism, AdelaideNow reports.

"There has been a massive 'go' for Americain and all we can put it down to is the Ollie factor,'' TAB's Adam Hamilton said. "The money has just kept coming for the horse since it was learned Damien Oliver was the new jockey.

"We certainly didn't see the plunge coming, the sheer volume of money for Americain since Saturday has really surprised us but it certainly shows how popular Ollie is with punters.''

Mosse rode Americain when the French champ ran a close fourth to Dunaden in the Caulfield Cup last start.

Americain was three deep for most of that race and his effort to just miss a place was nearly as good as the winner's.

Owners Kevin and Colleen Bamford, and Gerry and Val Ryan, then decided Mosse's time was up.

"We felt we needed an Australian jockey,'' Gerry Ryan said.

It was a change of fortune for Oliver who had been dumped as rider of Cups contender My Quest For Peace prior to the Caulfield Cup following reports that alleged the jockey had placed a $10,000 bet on a horse he was riding against, eventual winner Miss Octopussy, at Moonee Valley two years ago. The allegations are being investigated by stewards.

Oliver has an excellent record when riding international stayers in the Melbourne Cup.

Oliver famously rode Irish stayer Media Puzzle to Melbourne Cup victory in 2002, just days after his brother Jason had been killed in a barrier trial incident in Perth, and he has also finished second on Japan's Pop Rock (2006) and England's Purple Moon (2007). He also won the race on Doriemus in 1995.

Americain, who was restricted to light exercise at Werribee trackwork yesterday, has 58kg in the Melbourne Cup next week and meets Dunaden on better weight terms after that horse was penalised 1kg to 59kg for his Caulfield Cup win.

Dunaden remains a solid second favourite at $6 in Melbourne Cup betting ahead of English stayers Mount Athos ($9) and Red Cadeaux ($10), followed by the first Australian-trained stayer, Maluckyday ($13).

Read more at AdelaideNow.