Emerging forward Nate Caddy's career-best six-goal haul wasn't enough for the Bombers in their 16.9 (105) to 14.11 (95) defeat to the Power in Sunday's dead rubber at Marvel Stadium.
The result left wooden spooners Essendon with a 2-21 record for the year, worse than even the 2016 'top-ups' season which generated three wins.
The Bombers also won only two games in the 1933 VFL campaign, though that was in a shorter 18-round home-and-away season.
Interim coach Dean Solomon will hand the reins to a new full-time appointment in the coming days, with Essendon looking to usher in a new era.
It could be one without former captain Zach Merrett, who tallied a game-high 32 disposals against Port amid speculation he could again attempt to force a trade after being denied the chance to join Hawthorn last year.
Caddy shone in attack but the Power had their own star at the other end as Mitch Georgiades kicked five goals.
Mitch Zadow and Jack Whitlock added two important goals each in the second half, while Jase Burgoyne (30 touches, two goals) and veteran Ollie Wines (27, one) were also key contributors in a tight game.
Port's stand-in captain Georgiades booted the opening goal of the match and the visitors kicked 22 points clear before halftime in a bright start.
Caddy notched his fourth major before the main break and added a fifth soon after the re-start, which kicked the Bombers into action.
They added 4.1 to 1.2 in the third quarter, hitting the front when Angus Clarke (three goals) marked close to goal and converted in time-on.
Clarke added another to open the final term and Caddy brought home fans to their feet with his sixth.
Port came again, scoring freely from centre-bounce as a last-quarter shootout unfolded, with the lead changing hands five times for the term.
Merrett looked to have kicked the match-winner when he converted a free kick with less than two minutes left, before Georgiades hit back with a calm set shot and then helped set up the sealer for Whitlock.
Will Setterfield (32 touches) and Archie Roberts (27) were busy for Essendon, as was captain Andrew McGrath (25) in his 200th game.
