Giants 16.11 (107) Power 10.13 (73)
Greater Western Sydney cast further doubt on Matthew Primus's future at Port Adelaide with an incredible 34-point win at Skoda Stadium on Saturday.
Primus said prematch he was not entertaining thoughts of what might happen should the Giants record the second win of their short existence.
But that is now a reality, and the Power coach will face more speculation after his charges suffered an embarrassing loss.
View a gallery of pictures taken at the game by Carlos Furtado by clicking on the image below:
Giants ruckman Jonathan Giles, who spent four years on Port's list without playing a game, was arguably best afield. Chad Cornes kicked a clutch goal against his old team.
The Giants, who passed 100 points in a match for the first time, were pitched into a role they had never played before in Kevin Sheedy's 1000th match as a player and coach - front-runners.
The hosts raced to a 26-point lead at quarter-time and had built a 44-point buffer in the second term before Port found something and stopped the rot.
The Giants led at half-time for the first time in their fledgling existence, but the visitors made the most of the hosts' tired legs in a one-sided third quarter. Port took control and reduced the home side's advantage to just five points.
But the Power did it the hard way despite their dominance, one stretch of six consecutive goal-scoring chances netting just four behinds.
Their sloppy conversion proved costly, with the Giants' Jeremy Cameron boosting his side's lead to 12 points at three-quarter time after a slick pass from Callan Ward.
Still, most anticipated Port would finish stronger, yet it was the Giants who played with greater passion, kicking six goals in the final term to humble the visitors and climb off the bottom of the ladder.
Many of the Power's players fell to the ground after the loss, knowing the club boasts the ignominy of losing to both Gold Coast and the Giants in the expansion clubs' maiden seasons.
The Giants were expected to be competitive, but few foresaw the Power, who have recorded five wins this season, starting so sluggishly and devoid of confidence.
They refused to man up, struggled to move the ball meaningfully and were hammered at centre bounces - thanks, in no small part, to Giles.
And the hosts took advantage as Primus shifted uncomfortably in the coach's box. Port regained the ascendancy, but could not mount a second comeback when it was needed. Primus has now coached the Power to 13 wins from 47 games.
Meanwhile, Adelaide coach Brenton Sanderson said the Crows are good enough to win the flag but he was more concerned with beating Essendon today.
The Crows face the Bombers at AAMI Stadium in a game that could have a significant impact on the finals fortunes of both teams. A win for the home side would reaffirm their credentials as a top-two contender, while Essendon will look to shore up the team's place in the top eight.
Sanderson said there was no reason his team could not match it with other premiership contenders.
"We've shown great improvement," he said. "We've got five more home-and-away games to go and then we'll prepare for a finals campaign. But we'll keep our focus really narrow. We'll focus on Essendon this week."