Finding any challengers to take on the world's best horse on turf is proving problematic for the Moonee Valley Racing Club, whose Cox Plate field is shaping to be as small as the eight runners that lined up to take on Fields Of Omagh when he won in 2003.

It is not uncommon for the MVRC committee's hand-picked field to feature less than the capacity 14 runners, but Winx's utter contempt for her rivals during a 21-start unbeaten run is taking the Cox Plate into new territory.

Caulfield Stakes winner Gailo Chop, Epsom hero Happy Clapper, crack three-year-old Royal Symphony and Cranbourne Cup winner Folkswood are among the likely rivals for Winx, who is listed a $1.20 chance to equal Kingston Town's three Cox Plate triumphs.

Overseas-trained Kaspersky and The Taj Mahal are also potential Cox Plate starters, along with Kris Lees' Sense Of Occasion, but the most important race of the mare's career could also feature the smallest field she has faced since the three-horse Caulfield Stakes last year.

Yet Waller isn't the least bit concerned with the lack of genuine competition for what promises to be the most hyped race of the Melbourne spring carnival.

"I guess it's more up to Moonee Valley into what they let into the race," Waller said. "They have been pretty strict in what they let into the race in previous years. They've probably set a precedent. They can't say certain horses can't run it one year and then [they can] the next.

"But it's the least of my worries. That's the beauty of Winx. She's got to lose form and there's got to be a champion come forward and take her place [to be beaten].

"I haven't given it any thought and I haven't got into the argument about a couple of horses being there that potentially shouldn't have been there last start [in the Turnbull Stakes]. I went up to one of the trainers of the 200-1 chances and wished them all the best."

It is highly unlikely Winx will have any competition from within her own stable with Waller reluctant to run Toorak Handicap starters Egg Tart and Tom Melbourne after luckless efforts in last weekend's group 1 handicap.

It will have historians scrambling for the record books with Fields Of Omagh's eight-horse Cox Plate the least amount of runners to face the starter in arguably Australia's best race since 2000.

Northerly's back-to-back wins in 2001 and 2002 came in fields of just eight and nine runners, respectively.

But the decimated Cox Plate field will do little to diminish the enthusiasm for the race, which was fuelled by a massive build-up last year when Hartnell emerged as a potential stumbling block before Winx's mind-blowing eight-length romp.

"It's not Winx's fault if they don't get a full field [this year]," Waller said. "It was only a couple of weeks ago some people didn't think she was going that well. She's great and everybody was happy to see her win so well last start - as we were.

"I've been a trainer long enough to know it was hard to beat Black Caviar and you like to find a race you think your horse can win in. And I can see that effect with her. It's something I shouldn't discuss.

"It's a privilege that other people think that way. If there's other options for them to win it might be reasons for them to take another path."

Trainer Pat Webster confirmed Damien Oliver will take over the reins on Happy Clapper from Blake Shinn after the gelding's last-start defeat in the Craven Plate at Randwick.

Waller plans to nominate Winx for Dubai's World Cup carnival as well as other features throughout Europe next year after admitting a Japan Cup start was unlikely after a surprise nomination on Tuesday.

He would have also nominated for Hong Kong's international meeting if quarantine restrictions hadn't been tightened earlier this year.

"After the spring I'll sit down with the owners and see what they want to do," Waller said. "I just said to the owners, 'We'll put a few noms in and keep options open'."