The Power lost Warren Tredrea to an ankle injury early on and trailed by two goals heading into the final term, but outscored the Bombers four goals to two before holding on in the frantic dying minutes to record a gutsy 17.7 (109) to 16.10 (106) win.
Daniel Motlop's decision at the 22-minute mark to play on for a booming 50m goal gave his side the lead, and despite Angus Monfries' reply to Justin Westhoff's third, the Bombers couldn't find another.
The match marked the fourth occasion this season that Port has come from behind at three-quarter time to take the premiership points much to the delight of coach Mark Williams.
"It's a great achievement for our club and our players to be able to draw from adverse conditions and to be able to keep coming and get over the line," Williams said.
"We've got a lot of confidence and a lot of real belief over the last few weeks. It's happened a lot of times this year so it can't be a fluke; it's really to do with their mindset.
"It was a great effort and all credit to the players."
Danyle Pearce was outstanding in his 100th AFL match with his 29-possession, two-goal performance earning him the praise of his coach. Kane Cornes was also busy around the stoppages with 29 touches of his own, while Williams described Dean Brogan's 44-hit-out game as 'lion-hearted'.
For Essendon, Jobe Watson led the way with 31 disposals while Angus Monfries played a pivotal role with 25 possessions and three goals.
Chad Cornes was prolific in an opening term that saw the Power make most of the running with the Bombers working to stay in touch.
Cornes had 13 touches as Port eked out a five-point lead at the first break, but he didn't register a possession in the second as Essendon took its turn in the driver's seat.
A Monfries double gave his side the largest lead of the match to that point, but Port took a hit when Tredrea rolled his right ankle and disappeared down the race midway through the quarter.
Essendon quickly set about adding to a one-point half-time lead with three goals in succession sending the visitors reeling, but just as the game threatened to escape them Power summoned an unlikely four-goal burst sparked by Motlop.
Scott Gumbleton's third restored some sort of order, but a 12-point advantage at the final change wasn't enough to give Essendon absolute control and the frenetic last quarter proved a fitting crescendo.
Essendon 3.1 7.3 14.8 16.10 (106)
Port Adelaide 4.0 7.2 13.2 17.7 (109)
GOALS
Essendon: Davey 3, Gumbleton 3, Monfries 3, Ryder, Zaharakis, Lovett-Murray, Melksham, Lonergan, Stanton, McVeigh
Port Adelaide: Ebert 3, Westhoff 3, Motlop 3, Pearce 2, Gray 2, Davenport, Trengove, Boak, C.Cornes
BEST
Essendon: Monfries, Watson, Lovett-Murray, Winderlich, Melksham, Stanton, Hooker
Port Adelaide: Pearce, Rodan, K.Cornes, Brogan, Cassisi, Boak, Ebert
INJURIES
Essendon: Hooker (cut head)
Port Adelaide: Tredrea (ankle), Krakouer (knee), Broadbent (TBC) replaced in selected side by Logan
Reports: Nil
Umpires: Stevic, Hay, Wenn
Official crowd: TBA at Etihad Stadium
The views in this article are those of the author and not necessarily those of the club.
