Only a win over the 14th ranked Bulldogs was required to secure their first playoff appearance in seven years, but despite coming back from 20-12 down at halftime, Bulldogs playmaker Lachlan Lewis kicked the match-winning field goal with two minutes remaining at ANZ Stadium.
The result leaves the Warriors vulnerable in eighth spot on the premiership ladder on 28 competition points, four points ahead of the ninth-ranked Wests Tigers.
With only two rounds remaining in the regular season the Warriors will continue to tread a tightrope towards the playoffs ahead of next Friday's crucial home game against Penrith and the final round encounter against Canberra at Mt Smart Stadium.
There are concerns however for the health of five-eighth Blake Green who was replaced with 11 minutes to go, and halfback Shaun Johnson who suffered an ankle injury in the second half but saw out the rest of the match.
The Warriors were heavily favoured to do the business over the Bulldogs but just as they did in their embarrassing defeat on the Gold Coast last month, they failed to play with the required intensity and paid the price.
After impressing with back-to-back wins over the Dragons and Knights, the Warriors attack lacked direction and energy while their defence through the middle was caught short as the home side controlled the speed of the ruck through strong running and quick play-the-balls.
Centre Gerard Beale and captain Roger Tuivasa-Sheck scored first half tries for the visitors but three four-pointers to Adam Elliot, Reimis Smith and Lewis were complemented by four goals to Rhyse Martin to give the Bulldogs an eight point advantage at the break.
Match officials missed a forward pass from Canterbury captain Josh Jackson to centre Kerrod Holland in the lead-up to Lewis' try, but the Warriors had only themselves to blame for letting the result slip away.
Both sides traded tries early in the second half with right wing David Fusitu'a scoring for the Warriors and centre Josh Morris replying for Canterbury, before Fusitu'a dived in for his second to leave the visitors trailing 26-20 near the end of the third quarter.
Forward Adam Blair produced an offload for replacement back Peta Hiku to dive over near the posts and halfback Shaun Johnson's fourth conversion brought them level with four minutes remaining, but Lewis's one-pointer broke the deadlock for good in the 78th minute.
Bulldogs 27 (Adam Elliot, Reimis Smith, Lachlan Lewis, Josh Morris tries, Rhyse Martin 4/4 cons, 1 pen, Lewis field goal)
Warriors 26 (Gerard Beale, Roger Tuivasa-Sheck, David Fusitu'a 2, Peta Hiku tries, Shaun Johnson 3/5 cons)
