Havana provided vindication for a difficult but necessary decision when he broke maiden ranks at Canterbury on Wednesday.

Trainer Paul Messara has long had a high opinion of the three-year-old and accordingly raced him in Group company last autumn and spring but he failed to live up to expectations.

The son of Starcraft was gelded and showed the benefit of the procedure at Canterbury.

"He's always been a classy horse. Gelding him has made all the difference and today it showed," Messara said.

Nash Rawiller took the $2.60 favourite to the front from an outside draw and he extended his lead in the straight to score by four lengths over Rock Temple.

The ease of Havana's win has given Messara the confidence to again look toward black-type races starting with the Listed Darby Munro Stakes (1200m) at Rosehill on March 29.

Havana provided the first leg of a treble for Rawiller who also scored wins aboard Shahad for Gai Waterhouse and Murphy's Delight for Chris Waller.

Lightly raced colt Rock Sturdy booked his spot on Joe Pride's carnival team with victory in Wednesday's theraces.com.au Handicap (1550m), a week after stablemate Mesmereyeser underlined her potential with a midweek win at the venue.

The performances by the pair have reignited Pride's optimism he can feature in the three-year-old races over the autumn.

"I had no three-year-olds who were standing out coming into the carnival and now I've got this horse and Mesmereyeser," Pride said.

"I've suddenly got two nice three-year-olds."

Stepping up to a middle-distance for the first time, Rock Sturdy trailed the speed and briefly looked to be in bother when Hugh Bowman angled for an inside run which didn't come.

But the Fastnet Rock colt was able to change course and accelerated quickly to sprint to victory by three-quarters of a length over Moorluv.

"He's a horse with a lot of class," Bowman said.

"I was disappointed for a run on the rails but I was able to ease out and balance him up and he showed what he could do."