Craig Williams celebrated his birthday and consolidated his position at the top of the Melbourne jockeys' premiership in winning style at Flemington on Saturday.

Thermogenic's hard-fought victory has pushed Williams to a three-win lead over Dwayne Dunn and Damien Oliver in the race for the jockeys' title.

It also continued the successful Victorian run of Morphettville trainer Phillip Stokes who landed his eighth Melbourne metropolitan winner for the season.

Backed from $10 to $8.50 in the Henry Bolte Handicap, Thermogenic stayed on to score a half-neck win from Mr Pago ($16) with Magic Boy ($9) a short head away third.

Williams, who turned 38 on Saturday, wasn't worried about being caught wide.

He said he knew he was on a fit horse because Thermogenic had been targeted at the South Australian Derby but didn't make the field.

"I was able to keep him focused and when I asked him to deliver he was very solid up the straight and through the line," Williams said.

Norm Saade, representing Ultra Racing, said Thermogenic was sent to Melbourne with the aim of increasing the horse's rating ahead of a spring campaign.

Thermogenic could now head to Brisbane for the Queensland Derby at Doomben on June 6.