Previous race day experience has given Godolphin colt Tessera an edge over a couple of well-fancied debutants in the Canonbury Stakes for two-year-olds.

The much-spruiked Defcon found the occasion a little too much and used up a good part of his nervous energy behind the gates before Saturday's Group Three race, the first stakes race in Sydney for juveniles this year.

Punters rallied to another newcomer, Star Of Monsoon, who was sent out the $3.40 favourite but struggled in the wet ground.

For Tessara ($4) it was a replica of his first start two weeks ago, with James McDonald taking the colt to the front from the outset.

Defcon ($4) was slowly out and rallied in the straight to put his nose in front but Tessera came back to beat him by 1-1/2 lengths.

Mount Panaroma was third with Star Of Monsoon fourth.

"I was going to take him to Melbourne for the Talindert Stakes but I think he's better than that," winning trainer John O'Shea said.

"He's two from two now and very professional.

"He's an unassuming horse and he loves a scrap.

"The plan now would be to have one more run into the Slipper."

Tessera remained a $15 chance for the $3.5 million Golden Slipper after the Canonbury with markets headed by Defcon's Peter and Paul Snowden-trained stablemate Capitalist.