Having won just one of their previous 30 games, the Bombers finally played with a sense of urgency to give Dean Solomon his first win in his 10th match as a caretaker coach, which includes three at Gold Coast in 2017.
Leading at every break, Essendon gave up their advantage twice in a frantic final term but hit back through clutch goals to Sullivan Robey and Peter Wright.
With a wildcard spot still up for grabs, the Giants desperately tried to reclaim the lead in the dying stages, but Essendon hung on for a famous win - 10.7 (67) to 8.16 (64).
It was Essendon's first win since beating Melbourne in Gather Round in Adelaide on April 11, while they hadn't won a game in Victoria since May, 2025.
The Bombers, who were ravaged by Brisbane last Sunday and had lost 12-straight matches, were given virtually no hope of matching it with the red-hot Giants.
But it does continue GWS' baffling trend of struggling against lower-ranked opposition, but managing to dismantle last year's grand finalists Brisbane and Geelong, as well as rampaging ladder-leaders Fremantle, amid their previous seven games.
As well as the Bombers, GWS have dropped matches to St Kilda (twice) and West Coast.
In a further concern for the Giants, they lost captain Toby Greene to a serious-looking quad injury during the third quarter.
GWS were demolished in the clearances 45-28, as Essendon aces Zach Merrett (35 touches, one goal) and Sam Durham (25 disposals) rediscovered some form.
Further delighting the home crowd, former Essendon forward Jake Stringer endured a horror match in front of goal to finish with 0.7 on a wayward night for the Giants.
The only concern for Essendon was young star Nate Caddy, who was sent to hospital due to an elevated heart rate.
Caddy, who recently re-signed until the end of 2031 in a massive boost for the battling Bombers, didn't return to the ground after quarter-time.
The 21-year-old was looking weary speaking to Solomon and was taken straight to the rooms.
Essendon football boss Daniel McPherson was seen engaged in serious conversation with medical staff on the bench while Caddy was assessed underneath Marvel Stadium.
He was soon ruled out with illness in the second quarter, with Essendon later detailing the heart issues.
The result could prove costly for GWS, who would have jumped into 10th and a wildcard spot, had they beaten the Bombers.
It also lifted Essendon to 17th, sending Richmond to the bottom of the ladder.
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