The 18.9 (117) to 10.13 (73) defeat leaves the Bombers in the eight, but with plenty of soul searching ahead this week with the Saints to come next Friday.
Dustin Fletcher was back after suspension, but bad luck followed him across the continent as he lost at least a couple of teeth in an accidental third-quarter clash with Andrew McDougall.
Fletcher's teeth were preserved in milk as he returned to action and he left the stadium during the final term for treatment to re-attach his teeth.
There was a bonus for the Bombers with Eagles skipper Ben Cousins a late withdrawal due to injury, missing his first game since round 17 of the 2000 season.
In his absence, Chris Judd was elevated to captain in just his 61st AFL game.
Judd was good early with eight touches in the first term and Chad Morrison played his best game for years, running hard and using it well through the midfield.
Although the West Coast midfield made delivery into the Bombers' forward line tough, Darren Glass had the better of Matthew Lloyd who kicked eight last time these teams met.
Ted Richards, who booted three and Lloyd with two were Essendon's only multiple goal-kickers.
Damien Peverill, Joe Misiti and Jason Johnson worked hard, but the West Coast pressure was enormous.
After seven goalless minutes, West Coast finally put a major on the board for the first goal of the game after Chad Morrison marked and goaled from 40 metres.
Two minutes later, Phil Matera snapped brilliantly from the line at 40 metres but Nathan Lovett-Murray replied immediately with a cool goal on the run from 30.
The next goal came from a terrific passage of play after Adam Hunter took the bravest of marks in front of a thundering Matthew Lloyd, Rowan Jones another good one on the wing before McDougall soared over the back of the pack for a third good mark and goal.
In the last 10 minutes of the term, West Coast goaled three times, through Ashley Sampi (2) and another to McDougall to take a 31-point lead into the first break.
West Coast extended its lead to 34 at the long break after Quinten Lynch kicked the only goal of the term, booting it through nearly goalpost high from 55 metres.
With the game effectively over, Essendon kicked four in the third, but West Coast kicked five to increase their lead and maintain total control of the match.
In the last, it was more of the same, with West Coast just doing enough to maintain control of a game that was won much earlier.
Essendon coach Kevin Sheedy said the Bombers, who play St Kilda and Port Adelaide in the next fortnight, were struggling just to make the finals.
“We have just got to try and make the finals,” Sheedy said.
“The next six will decide and it starts next week. We’ve got St Kilda and Port Adelaide coming up, they are big games and big teams.
“We just have to make sure we play better than we did.”
Sheedy said he took some positives out of the form of youngster Kepler Bradley and Richards.
West Coast: 6.5 7.7 12.8 18.9 (117)
Essendon: 1.4 1.9 5.11 10.13 (73)
Goals: West Coast: Matera, McDougall, Sampi 3, Seaby, Morrison 2, Lynch, Judd, Adkins, Braun, Banfield
Essendon: Richards 3, Lloyd 2, Lovett-Murray, Hille, Stanton, McPhee, Solomon
Best: West Coast: Judd, Wirrpunda, Morrison, Glass, Hunter, Adkins, Lynch
Essendon: Peverill, Misiti, J Johnson, Richards, McPhee, Solomon
Injuries: West Coast: Hansen (hamstring)
Essendon: Fletcher (teeth), McVeigh (corked thigh)
Changes: West Coast: Waters in for Cousins
Essendon: Nil
Reports:
Umpires: Vozzo, James, Ryan
Crowd: 40,674 at Subiaco Oval
