The Bombers appeared in danger of letting Sunday's clash at Marvel Stadium slip after an ugly opening half, where they kicked just three goals along with 10 behinds and five shots that missed altogether.
Instead, Essendon flicked the switch late in the third quarter and kicked away early in the last to seal an 11.22 (88) to 11.9 (75) victory.
Stringer booted 4.6, including nailing an awesome barrel on the run while spurning several good opportunities in a performance that just about summed up the Bombers' day.
Long-kicking running defender Mason Redman (26 touches) was superb and Zach Merrett (28 touches) and Darcy Parish (30 disposals, seven clearances) racked up the ball at will.
Brilliant Giants ballwinner Tom Green (34 touches) was typically prolific and Josh Kelly (28 touches, two goals) also impressed, while Harry Himmelberg booted three goals and Nick Haynes was busy down back.
Brad Scott's Bombers made a bizarre late team change, dropping ex-skipper Dyson Heppell, whose form had been under fire, for ruckman Andrew Phillips.
Heppell was named the substitute and returned to the fray in the second quarter when Sam Weideman had to leave the game with concussion after he was clattered by Haynes in an aerial contest.
Key forward Weideman's exit forced the Bombers to swing Kyle Langford forward.
But where the Bombers had butchered their chances, with Jye Caldwell also among the main culprits, GWS largely found a way to convert theirs and led by 10 points at the main change.
Bombers coach Brad Scott looked in disbelief when Jye Menzie sprayed through Essendon's 12th behind, their 10th off the boot, late in the half.
Skipper Merrett stopped the rot when he snapped truly at the start of the third quarter and it turned the match into an arm wrestle.
Alwyn Davey Jr had some tests on his right arm shortly after and went down into the rooms.
The youngster returned to the field midway through the quarter and showed good poise in teeing up Stringer to put the Bombers in front.
GWS regained the lead but when Draper drew the Bombers level again late, it kicked off a run of five consecutive Essendon goals.
Redman kicked a goal on the run to give Essendon a six-point lead at the final change.
Stringer's monster goal from 60m out early in the final term pushed the margin beyond four goals and while the Giants surged late, they were unable to overrun the Bombers.