As a colt We're Gonna Rock had unlimited ability and a limited future.

After his first start as a gelding at Flemington on Saturday it seems highly likely he will fulfil his potential.

Equal favourite We're Gonna Rock ($6.50) scored the best victory of his career in the Group Two Bobbie Lewis Quality (1200m) and seems set to pick up something even better as the season progresses.

"We had to geld him because he was getting too big for his joints and knees," said trainer Mark Kavanagh.

"Now he's in proportion and he can go on with it."

We're Gonna Rock dived through late to beat the Queenslander Spirit Of Boom ($13) by a half head with Title ($15) 1-1/4 lengths further back in third.

As much as the race provided an answer for Kavanagh and the winning connections, it raised a couple of obvious questions over other runners.

Most notable among them is the glamour mare Mosheen whose return to racing had been postponed by a minor throat operation last month.

Mosheen raced in the second half of a tightly-packed field but showed no dash in the run home, finishing 13th.

Trainer Robert Smerdon said the throat problem had not re-emerged, but was at a loss to explain the performance of a mare who had been one of the stars of last autumn.

"She was a bit plain," Smerdon said.

"We have to hope she can bounce off that and improve considerably."

Mosheen is now likely to be stepped up to the 1400m of the Group One Sir Rupert Clarke Stakes at Caulfield on September 30.

The much-vaunted Shanghai Warrior also put in an inexplicably poor run, having scored brilliantly at his previous two starts.

Trainer Pat Hyland said he was mystified by an effort that was "too bad to be true".