GWS took three quarters to shake off Essendon’s fierce challenge, eventually posting a 27-point AFL win at Etihad Stadium.
After a below-par first half, the Giants showed too much class in the Sunday twilight match and won 17.15 (117) to 12.18 (80).
Midfielders Callan Ward and Tom Scully starred for the Giants while Toby Greene kicked four goals.
Essendon small forward Orazio Fantasia kicked 4.4 and defender Anthony McDonald-Tipungwuti also impressed.
The win keeps GWS within one game of the top four, while the Bombers were much-improved after heavy losses in the last fortnight to Fremantle and Hawthorn.
The Giants kicked six goals in the last quarter as the Bombers sprayed a wasteful 2.7.
The signs were ominous when GWS kicked 1.1 in the first couple of minutes.
But it was the Giants wasting their opportunities early, kicking six more behinds.
Essendon hit back with four goals and improbably led by 10 points at quarter time.
With Fantasia prominent and midfielder David Zaharakis continuing his fine season, the Bombers kept pressing in the second term.
The Giants problems compounded in the second term as Phil Davis (ankle) and Stephen Coniglio (shoulder) were hurt.
The Bombers led by two goals at halftime – other than their round-two win over Melbourne, only the second time this season they have been in front at the main break.
Essendon’s average score per game this season before Sunday was 58 – at halftime they had kicked 9.8 (62).
But Davis and Coniglio were able to play out the game and after an even start to the third term, GWS went up a gear.
They kicked four goals to one in the third for an eight-point lead.
Crucially for Essendon, Fantasia had to come off just before three-quarter time when he and Giants defender Nick Haynes clashed heavily in a marking contest on the outer wing.
Haynes landed heavily on his back and also had to leave the field.
While Haynes soon returned, Fantasia was on the bench for several more minutes as he had a concussion test.
Essendon kept pressing in the last term and midway through only trailed by two goals.
But a three-goal burst to GWS sealed the result, with Greene kicking three of his four goals in the last quarter.