Hong Kong-based jockey Brett Prebble answered the call from Gai Waterhouse to deliver a Group One result on Wandjina in a thrilling Australian Guineas, capping a huge day for the champion trainer.

Prebble, who got the call to ride Wandjina in Saturday's feature at Flemington after Damien Oliver was suspended, guided the colt to an all-the-way win as he staved off a late charge from Alpine Eagle who had fellow Hong Kong-based Douglas Whyte in the saddle.

Wandjina's win gave Waterhouse her second Group One of the day after Cosmic Endeavour's Canterbury Stakes success in Sydney.

A Caulfield Guineas placegetter in the spring, Wandjina had been aimed at the Australian Guineas (1600m) since his unplaced Cox Plate run in October.

Prebble won two Melbourne premierships in 1999-2000 and 2000-01 before moving to Hong Kong and Saturday's win was the Australian's first Australian Guineas triumph.

His hit-and-run missions back home have included a Melbourne Cup win on Green Moon in 2012 and a Golden Slipper on Crystal Lily in 2010.

"It's a great buzz," Prebble said.

"It's my first Group One for Gai Waterhouse and a Guineas I always wanted to win.

"This sort of race makes them as stallions and I'm sure the owners are going to be pretty happy with that."

Prebble thanked some friends who put his hat into the ring for the ride after Oliver was ruled out, and he was more than happy to make the trip.

Wandjina ($8) kicked when Prebble asked him to go in the straight and responded late to hold off Alpine Eagle ($4.80) by a half-neck with Stratum Star a long neck away.

Favourite Kermadec ($3.10) had his momentum halted at a crucial stage in the straight and had to change course before charging late for fourth.

His jockey Nash Rawiller, another now based in Kong Kong, labelled Kermadec a "certainty beaten".

Prebble was aware Whyte, a South African who won 13-straight Hong Kong premierships until his run was ended by Zac Purton last year, was closing quickly on Alpine Eagle from midfield.

"He (Wandjina) dug deep and obviously the second horse is a good horse as well," Prebble said.

"He (Wandjinda) is a serious weight-for-age miler I think."

Tony McEvoy was proud of Alpine Eagle's performance to get so close on a seven-day back-up while Whyte says the colt will only get better.

"He's a lovely horse. I wouldn't say the better horse beat him on the day, I'd say the greener horse beat himself on the day.

"Mentally, once the penny drops he'll be able to take the next step."