Champion Winx is the racehorse for all occasions and all conditions.

That's why her trainer Chris Waller says there's no need to over-analyse things heading into the mare's bid to extend her winning streak to 21in Saturday's Group One Turnbull Stakes at Flemington.

The mighty mare, rated the world's best horse on turf, has only six rivals in the Turnbull (2000m) with betting suggesting dual Group One winner Humidor, a $4.20 chance compared to Winx at $1.18, is the only danger.

The field also includes two horses rated $301, Magicool and Skyfire, with that pair 48 and 71 rating points respectively below Winx.

"The beauty of Winx is she can adapt to all situations," Waller said.

"Whether it be a three-horse field, whether it be a big field, whether it be a handicap, weight-for-age or set weights and penalties race.

"Track conditions are the same. Some horses you're watching the weather and every cloud that's coming onto the horizon.

"But with a horse like Winx - wet tracks, hard tracks, it's no problem.

"We won't over-analyse things and that's the beauty of (jockey) Hugh Bowman. He lets the horse be where she's comfortable, and she does the rest."

Waller selected the Turnbull for Winx's fourth start this spring believing the three-week gap was ideal after her most recent win in the George Main Stakes at Randwick, with another three weeks to the Cox Plate.

His focus is to ensure Winx is in the best possible condition as she continues her path towards a crack at a record-equalling third Cox Plate win.

And he believes she is.

"I just think she's dead-set flying," Waller said.

Winx is striving to join Kingston Town as a three-time Cox Plate winner on October 28 but before then, a win on Saturday would put her equal with him on 14 Group One wins, only one behind Black Caviar's record.

Winx has been forced to work overtime in her three Sydney starts this spring but having taken into account what she has had to do to win those races, Waller is convinced the six-year-old is going at least every bit as well as previous campaigns.

The mare has settled in well in Melbourne and delighted connections in a Flemington course proper gallop on Monday before a three-quarter pace hit-out on Thursday.

"Don't worry, she's going fantastic," Waller said.

"The 2000 metres will suit. She loves left-handed tracks, and if Monday morning was any indication of what we're in for on Saturday and in weeks to come, I don't think we'll be too disappointed."