Trainer Chris Waller says connections are weighing up if Melbourne Cup favourite Via Sistina will race, but international Jan Brueghel has been ruled out.

Melbourne Cup favourite Via Sistina is still no certainty to start, with trainer Chris Waller saying a decision is yet to be made following her stunning Cox Plate victory.

Via Sistina became the world's top-ranked horse on the back of her eight-lengths win in course record time last Saturday at Moonee Valley.

While Waller was track-side at Flemington on Tuesday to watch his spring carnival charges go through their paces, Via Sistina was spending some recovery time at a farm.

The Kiwi mentor, who trained legendary mare Winx, said the connections of Via Sistina were still weighing up whether she would saddle up for the epic 3200m race on November 5.

Bought by Yulong Investments for $5.5 million in December last year, Via Sistina smashed Winx's race record in the 2040m Group 1 feature.

"It's only a couple of days after the race (Cox Plate) so it's a bit early for a decision, so we need a few more days, it will be later in the week," said Waller, who won the 2021 Melbourne Cup with Verry Elleegant.

"We're still waiting to see how she comes through the run. It was an amazing win.

"It's been great to see that she's been rated the highest-rated horse in the world, which really did show how good the win was, so we're still enjoying the celebrations of that victory.

"Most importantly just seeing how she is as a horse, in terms of going to that career-best high and what it takes out of her - she seems fine, but you never really know until a few more days, so we're just trying to preserve her to ensure that wasn't just a one-off.

"My job is to get her to win not just one race but many races, and to advise the people that own the horse what's in her best interest."

Jockey Damien Lane, who will ride another Waller-trained Cup mount Kovalica, finished second in the Cox Plate aboard Prognosis and described Vis Sistina as a "freak".

"He (Prognosis) was great and we couldn't have been happier with how he ran," Lane said.

"We thought we executed the plan well, but we were beaten by a freak on the day.

"Via Sistina was incredible ... I wanted to run the quickest 2000m I could and achieved that and when she came past me it was a shock."

The Group 1 Champions Stakes at Flemington on November 9 is another option for Via Sistina, or she could target the $8 million Hong Kong Cup (2000m) in December.

While the racing world waits on that call, European star Jan Brueghel has been ruled out on veterinary advice following a CT scan.

Irish trainer Aidan O'Brien's stallion was the Cup favourite before Via Sistina's barn-storming Cox Plate run.

A Racing Victoria statement didn't specify an issue, but said the Irish four-year-old was "at heightened risk of injury".

Meanwhile, racing queen Gai Waterhouse insists her Cup chance will live up to his name - Just Fine - after finishing dead last in Friday's Moonee Valley Gold Cup.

"He's a quirky horse," Waterhouse said from Flemington.

"We went to the Gold Cup thinking he'd run very well, hoping we wouldn't get the (weight) penalty and we certainly didn't, so we come in with 53kg on a track he's been successful on.

"He's been set for the Cup and it's happened before, horses have run poorly on different tracks and races and he's fine, he's just fine.

"His bloods are well, he's eating well, so why shouldn't he run."

More than 30 horses remain on the Melbourne Cup list of acceptances, with the final field to be confirmed after Saturday's meeting at Flemington.