In perhaps the most remarkable ending to an AFLW game ever seen, a 50-metre penalty has allowed GWS’ Kat Smith to kick the first after-the-siren matchwinning goal in league history.

St Kilda, winless this season, hit the front with three minutes left after Tarni White won a holding-the-ball free kick and slotted a brilliant long-range goal.

White had two similar long-range shots in the second-last minute of the match and rather than chipping it to a teammate to burn the clock, she took a shot on goal both times, resulting in just one point being scored for a four-point Saints lead.

The Saints kicked the ball forward with 30 seconds left but the Giants flung it desperately down the grandstand-side wing, with Kat Smith marking 70 metres out with five seconds left.

She kicked desperately forward to Cora Staunton but a 50-metre penalty was then called, and it was unclear why.

There did not appear to be anyone in the protected zone; the commentators speculated that it was either for Bianca Jakobsson knocking the ball out of Smith’s hands after the mark, or Kate Shierlaw appearing to send a Giants opponent to the ground off the ball.

Shierlaw was seen in tears on the broadcast and the timing of the penalty suggested it was her incident that gave away the 50.

Smith kicked truly from 20 metres out on a 45-degree angle to give the Giants a famous two-point win.

It was reminiscent of Jim Stynes running over the mark and giving away a 15-metre penalty in the 1987 preliminary final that allowed Hawthorn’s Gary Buckenera to kick the winner and beat Melbourne - if not quite with the same stakes.

The match followed two consecutive AFLW thrillers, as Melbourne held off a post-siren shot on goal to beat Brisbane on Monday night, while the Bulldogs stormed back from four goals down at three-quarter-time to draw with Gold Coast on Tuesday.