In what was surely one of the biggest boilovers in the short history of the AFLW, St Kilda, in their first season and rated a $101 shot to win the flag, triumphed 3.1 (19) to 1.8 (14) against the wasteful and inaccurate Demons.

Melbourne's loss was compounded after Maddy Guerin appeared to dislocate her kneecap and Irish rookie Sinead Goldrick suffered a concussion in the second quarter.

The Demons dominated the inside-50 count 31-17 as well as the scoring shots 9-4, while they also had more disposals, contested possessions, tackles and hitouts.

But they couldn't make it count on the scoreboard and the plucky Saints made them pay a heavy price.

Melbourne coach Mick Stinear described it as a "tough night".

"There are two ways to look at it - if we kicked a little straighter, we might be on the right end but then I think fundamentally, the way we played we just didn't execute and play our roles the way we would've liked," Stinear said.

"The Saints' pressure was good and they denied us opportunities going inside 50. I think we could've masked it with a few less points and a few more goals, but ultimately we want to be a better performing team than that."

St Kilda coach Peta Searle hailed a "special" performance from her players and never doubted they could get the job done.

"I've got good belief in our group," she said.

"I think it was more about whether they had the belief and they certainly demonstrated that they did ... this week we played the four quarters.

"Melbourne are a class outfit, a great defensive side the way they get into safety and their numbers behind the ball, it was tough to score against, but we adjusted and they found a way."

Caitlin Greiser (11 disposals and four marks) was outstanding for St Kilda, having a hand in each one of her team's goals, scoring two, including a match-winning bomb from 50 metres out, and setting up the other.

For Melbourne, vice-captain Karen Paxman stood out with 26 touches (13 contested) and six clearances.

Melbourne dominated the first quarter with 14 of the first 18 inside 50s, including the first eight of the game.

But wastefulness in attack and a grim St Kilda defence rendered the Demons incapable of capitalising on a strong breeze and they had to settle for a four-point lead at quarter-time.

The Saints continued to absorb the Demons' pressure in the second term and were rewarded late in the first half when Darcy Guttridge goaled against the run of play to ensure the hosts enjoyed a one-point lead at half-time, despite Melbourne doubling them for forward entries (20-10).

The arm wrestle continued in the third term with just three behinds all scored by Melbourne handing them back a slender two-point advantage at three-quarter time.

But the Dees were held scoreless in the final period and when Greiser spectacularly split the big sticks at the seven-minute mark, it proved to be enough for an historic result.

Australian Associated Press