It seems St George Illawarra’s late season fadeout is officially over. The form guide was thrown out the window after a first half hat-trick by Tariq Sims propelled the Dragons to a stunning 48-18 NRL elimination final win over title contenders Brisbane at Suncorp Stadium.

The Dragons booked a semi-final showdown with South Sydney on Saturday with the seven tries-to-three romp in front of 47,296 fans – St George Illawarra’s first victory at the venue since 2009.

Remarkably the Dragons did it without playmaker Gareth Widdop (shoulder), James Graham (concussion) and NSW lock Jack de Belin (ankle), after they failed to finish the game. It marked the first time the Dragons had won a final since claiming the 2010 premiership.

Brisbane are suddenly out of the title race after having their streak of seven straight finals wins at Suncorp sensationally snapped. The Dragons weren’t expected to show much resistance after leading the ladder up until round 16, only to limp into the finals in seventh with six losses in their past nine games.

And the omens weren’t good when Brisbane jumped to a 10-2 lead after 17 minutes. But St George Illawarra came alive off a string of Korbin Sims errors to pile on four tries in 18 minutes – including three to brother and backrower Tariq Sims – to snatch a shock 28-10 half-time lead.

They didn’t have it all their own way as Brisbane threatened to launch a comeback when Widdop came off in the 55th minute after aggravating a shoulder injury that had sidelined him for the last three weeks.

The Broncos crossed twice through skipper Darius Boyd (52nd) and halfback Kodi Nikorima (55th) in three minutes to cut the deficit to 34-18 and give the stunned local fans hope. But the Dragons stood up with ex-Broncos halfback Ben Hunt steering his team without Widdop in a happy homecoming after copping vile social media abuse during his side’s late season stumble.

Brisbane lost key forwards Joe Ofehengaue (concussion) and David Fifita (ankle).

Instead of another title, Brisbane coach Wayne Bennett is now expected to contemplate his future after the Broncos board knocked back his proposal to stay on to the 2020 season. He is locked in for 2019 but there is speculation Bennett may not see out his contract. It was Bennett’s 27th finals campaign and 65th finals match.