Disappointment has quickly turned to joy for jockey Jason Collett who won the opening race on Winx Stakes day at Randwick after originally being earmarked to ride a rival runner.

Collett had been pencilled in to partner Bellarina Magic for Brett Cavanough in the TAB Highway Handicap (1100m) but could not make the filly's weight, instead jumping aboard stablemate and eventual winner Charlotte's Heart.

"When I saw the stablemate got 53 (kilograms), she looked the better ride so I was disappointed not to be riding it, but it worked out good for me in the end," Collett said.

One of three Highway Handicap (1100m) runners for Scone-based Cavanough, Charlotte's Heart ($9.50) settled midfield and tracked up behind the leaders before having to shoulder her way clear in the straight.

Once she got galloping room, she accelerated quickly to score a comfortable 1-1/2 length win over Revitup Rednut ($21) with Galaxy Force a half head away ($7).

The win was Charlotte's Heart first since a Moree victory in May and Cavanough said it was well deserved after she struggled to handle a heavy track at her most recent trip to town.

"She hit a wet track and she's been plagued by wide barriers since," Cavanough said.

"Today was D-day, she's one of those horses we thought might have found her mark.

"We were going to sneak her up to Queensland. We've been going to go everywhere but this race presented, she drew a good gate so that's it."

There were some hard luck stories behind the winner, including Lady Demi who got a long way back and ran into several dead-ends in the straight to wind up sixth.