Trainer Guy Walter is keeping a lid on ambitions for Jacquinot Bay despite the horse's return to winning form at Randwick.

After three disappointing efforts this campaign, Jacquinot Bay ($10) raced on the speed in Saturday's Percy Sykes Tribute (1600m) and was tenacious to the line, holding off the late finish from Smart Moochi ($19) by a short half-head.

Kerrin McEvoy stepped in to replace the injured Peter Robl on Jacquinot Bay who took his record to seven wins from 14 starts.

Walter was critical of the leaders' bias at Rosehill at Jacquinot Bay's past two starts but said the circumstances were different at Randwick.

"He was stepping up to 1600 metres and there didn't seem to be a lot of speed in the race," Walter said.

"I told Kerrin to try to be a bit closer but I admit I didn't expect him to be as close as he was.

"It is great to see him back winning. I don't think I trained him well last preparation.

"We were a bit ambitious and were trying to aim too high so we'll just wait and see what happens now.

"And while he has been disappointing at his past couple of starts, he now has the record of seven wins from 14 starts and not many horses can do that.

"It shows how consistent he is."

The race was named in honour of renowned veterinary surgeon Percy Sykes who died on Monday.

"I'm very proud to win the race named after Percy Sykes," Walter said.

"He was a giant of the industry."