Punters waiting for boom galloper Gun Case to make his metropolitan debut weren't disappointed when he scored an easy win at Doomben on Saturday.

The gelding has been rated among the most promising horses in Brisbane on the strength of two trial wins and Coffs Harbour maiden victory.

Gun Case, the $1.50 favourite, gave jockey Glen Colless a few anxious early moments on the big track but once he found his confidence the gelding strolled home to beat Tambo's Jewel ($11) by 3-1/2 lengths in the Novotel Novotel Brisbane Airport Handicap (1200m).

Trainer Liam Birchley thought enough of Gun Case to take him to Sydney for his first start where he finished fifth in Rosehill race.

Gun Case was then spelled and brought back to win a Coffs Harbour maiden on August 7.

Birchley will keep Gun Case in Brisbane to earn more prize money before deciding whether to head to Melbourne this spring.

"I have always had a wrap on him but immaturity has kept him away from the races until now," Birchley said.

"He had an accident at the track when he lost his rider and he was out for four or five months."

"We took him to Coffs Harbour for the experience of travelling and today was to see how he handles wet tracks."

Jockey Glen Colless said at the 800m he was concerned but Gun Case had been too good.

Meanwhile, smart three-year-old filly Pienkna ($3.20) ticked another box for a possible Melbourne trip with a win in the Australian Open Polo Doomben Handicap (1200m).

Trainer Tony Gollan said he would make a decision next week whether Pienkna would join stablemates Alma's Fury, Looks Like A Cat, Traveston Girl and Temple of Boom in Melbourne.

"It showed today she could handle a wet track which could be a help in the south," Gollan said.

"But I want to have a good think before I commit her.

"I have always rated her among my best horses but it is only her first preparation."