SYDNEY star Isaac Heeney has had a licence to thrill throughout his career, but since being handed the keys to the Swans' midfield has found career-best form and now willed his side into a preliminary final.

Heeney put on a midfield masterclass as he first battled to keep the minor premier within striking distance as Greater Western Sydney built a commanding lead and threatened to pull away, then led the stirring fightback on Saturday afternoon. And he did it all with a broken nose.

The 28-year-old gathered 30 disposals with 18 contested, seven clearances, eight score involvements and three goals of his own that included a monster from the middle of the SCG that levelled the scores with three minutes remaining. Joel Amartey goaled a minute later to snatch the win, but there was little doubt who had urged the Swans over the line.

"I sort of pride myself on being the ultimate competitor," Heeney said. 

"I'll put my head over it and be as hard as I can, as clean as I can, and run as hard as I can. I back myself in a lot.

"'Horse' (coach John Longmire) has also just given me the licence throughout my whole career, but especially this year, to really just hunt the footy, and do what I do, and have fun while doing it. When it comes off, it's nice."

Heeney added to his lengthy highlights reel with a clever one-handed mark and goal on the brink of the main change when the Giants had his side on the ropes.

The two-time All-Australian later revealed that he played a starring role in the heated qualifying final despite having his nose broken "for the sixth time" from a head clash in a tackle during the third term, not that there was any sign of the knock slowing him down.

Heeney was fortunate to escape a more serious injury when climbing over Giants defender Jack Buckley to pull down a screamer that would have been a strong Mark of the Year contender were it not taken during the finals.

"I haven't really taken one all year. It felt all right, got up there and a little hanger," Heeney said.

"I'm thankful for Buckley. He actually grabbed me and flipped me around. Luckily, otherwise I would've ended up on my head. I might send him a message later and say thank you.

"I didn't even expect to get up there, to be honest. I sort of just leapt at it and, just playing off instinct, got a nice sit."

The Swans were able to defeat the Giants in a final for the first time in four attempts even while trailing at the first change for the 14th time this season.

But Heeney brushed off any concerns with the Swans' sluggish starts and backed his side to come from the clouds again if needed, as it had just done against its cross-town and in round 22 against Collingwood.

The pair of last-gasp victories have helped to reignite the Swans' season after they had failed to turn around a three-quarter time deficit on all four occasions when they had faced one earlier in the year.

"Obviously finishing first, you kind of become the hunted. You know everyone's going to come out there and want to start well," Heeney said. 

"It's also us on, on starting slow, and we’ve got to match them in the contest. But at the same time, a lot of teams are coming out there to really give us the one-two early and see how far ahead they can get. 

"I believe there's a belief there that teams know we can chase them down."