Chris Waller has not ruled out a potential showdown between super mare Winx and the up-and-coming Egg Tart when the world's best horse on turf attempts to win her third Cox Plate.

Sydney's premier trainer said he was reluctant to race two stars of his stable head-to-head in the Melbourne spring carnival but conceded it was a possibility if Egg Tart continued the exceptional start to her career.

The three-year-old headed for a spell after winning the Queensland Oaks at Doomben last weekend, the same race Winx used to open her Group One account in 2015.

In his weekly video review, Waller said Egg Tart could line up against Winx at Moonee Valley on October 21 if she followed a similar pathway and also won the Epsom Handicap at Randwick before heading to Melbourne.

However, he was initially downbeat about a clash between the pair because Winx was "a freak".

Egg Tart has won six of her eight starts including giving Waller his first Group One win in South Australia in the Schweppes Oaks at Morphettville on May 6.

"She's won her last six, including two Group Ones," Waller said.

"The way she's doing it, it really is quite special. She'll come back in the spring and be a force to be reckoned with.

"She could run in a Caulfield Cup. The 2400 (metres) won't be a problem."