The resurgence of St George Illawarra under the coaching of Paul McGregor has continued with the Dragons seeing off table-topping Brisbane 12-10 at Kogarah Oval on Friday night.
Touted as wooden spoon contenders after opening the season with back-to-back defeats, McGregor's side, possessing the best defence in the NRL, held off a furious late flurry of attacking raids from the visitors.
The Broncos were reduced to 15 men after skipper Justin Hodges was forced out with a recurrence of his hamstring injury before halftime.
Alex Glenn then sustained a serious facial injury midway through the second period but despite trailing 6-4 at the break, the Broncos took the lead through Sam Thaiday's converted try in the 55th minute.
But the Dragons clinched the win when English front-rower Mike Cooper powered over and his fellow countryman Gareth Widdop added the decisive extra two points.