Gameiro made it 11 goals in eight pre-season games as Graham Arnold’s men continued their impressive streak to overcome the defending A-League champion at Townsville Sports Reserve, with the Austria skipper weighing in with the second after the break.
Showing steel and resilience and no little flair, the Sky Bklues were more than a match for Mike Mulvey’s side with Gameiro pouncing in the 25th minute - sending a dving header past goalkeeper Michael Theo from a pin-point Alex Brosque cross.
Janko came on for his second appearance for his new club in place of Brosque in the 55th minute.
And he made his mark 15 minutes from time when he took possession 20 metres out before rifling the ball into the bottom corner of Theo's net.
The Roar played its part and Henrique could have scored in the 15th minute when he fired over from a Jack Hingert cutback when well placed.
And that came three minutes after the Brazilian squandered another opening.
Corey Brown was denied by Sky Blues keeper Vedran Janjetovic in the 79th minute when he tipped his looping header over the bar.
Then in the dying minutes Jean Carlos Solorzano whistled a shot just past right hand post. But it was too little too late for Brisbane.