The Wests Tigers turned in a superb second half to beat St George Illawarra 21-12 in Friday night's opening NRL finals match, leaving the Dragons with an anxious wait to know whether their premiership defence is over.

Behind 12-6 at the break, halfback Robert Lui starred as the Tigers stormed home and the Dragons suffered a meltdown that looked to extinguish any hope they have of going back-to-back in 2011.

Wayne Bennett's coaching era could be over by Saturday night after his side appeared first to rediscover and then lose their mojo in the space of 40 minutes.

The premiers will exit the finals if two teams among the Warriors, North Queensland or Newcastle have upset wins in this weekend's remaining games.

But even if they live to fight another day, Bennett will have a massive task to instil confidence back into a side that has won just two of their past eight games.

A ninth straight win for the Tigers, a club record for the joint venture, came after they were forced to rule out star centre Chris Lawrence before kick-off when he failed to recover from a hamstring injury.

Other results will determine whether Tim Sheens' men have next week off, a bonus they will earn if two of the top three sides go down.

For the Tigers, Benji Marshall, Beau Ryan and Chris Heighington scored tries, while Marshall kicked four from five and a field goal in front of 45,631 fans.

Mitch Rein and Jason Nightingale bagged four-pointers for the Dragons with Jamie Soward booting two from four.

The game began with one of the most bizarre tries ever seen in an NRL game, star five-eighth Marshall mis-kicking and appearing to drop the ball before it deflected off an opponent and he regathered to run 30m and score, the apparent knock-on deemed a drop kick by video referees Russell Smith and Chris Ward.

The Dragons looked to have their groove well and truly back when they dominated the first half to lead 12-6 after tries to Rein and Nightingale.

But the Tigers came out of the sheds on fire and they levelled the scores in the 47th minute when Ryan finished a Tim Moltzen bust started with a Lui inside ball.

They hit the front at 14-12 when Marshall booted a 53rd minute penalty goal, and it was 18-12 when Lui sent Heighington over 12 minutes later.

As the clueless-looking Dragons cruelled their chances with errors, Marshall put it beyond doubt with a 77th minute field goal and then added a penalty goal two minutes later.

As well as Bennett, who heads to Newcastle, stars Mark Gasnier (retiring) and Darius Boyd (Newcastle) could have been involved in their last games for the Dragons.

The fifth-placed side has exited in the past two seasons - the Warriors last year and Manly in 2009.

"I'll go home, try and get a good night's sleep and sit it out `til Sunday night, see where it all is," Bennett said.

"They got a roll-on in the second half and we just didn't get a look in.

"We should have been full of confidence (at halftime), we'd done a great job first half and it was our game."

Sheens, who said his side had "panicked" the premiers in the second half, believed the Tigers had dodged a bullet in the first.

"I think it's probably the worst half of footy we've played for a long time," he said.

"I can't believe for a semi-final we weren't 20 down.

"I suppose I've got to credit our defence for that."

Dragons captain Ben Hornby said his side could turn it around if they get back next week.

"We just need to carry on what we did in the first half in the second half and we would have been fine so there's no reason why we can't replicate that next week," he said.

Brought to you by AAP © 2024 AAP