A bittersweet win for Bristol City left them in the play-offs for a second consecutive year.
They had to win and QPR had to fail at Sheffield Wednesday to give them automatic promotion.
City fulfilled their part of the bargain with two early goals by Christian Roberts but Rangers were to prove the party poopers for a 19,000 sell out crowd.
Blackpool who lost their manager Steve McMahon on Thursday showed they were not there in a supporting role for City when Steve Elliott lashed in a volley from the right.
But they were soon under pressure as Tony Rougier began to test them with some well-directed crosses from the right.
His early ones were wasted, notably by Lee Peacock who sent a six-yard header straight at young keeper Lewis Edge.
But on 19 minutes Roberts responded to a Rougier effort to flick a goal to the area behind Edge's left shoulder.
Less than two minutes later the 17-year-old keeper, making his league debut, was retrieving the ball from the same spot, this time Roberts finishing a Tommy Docherty free-kick with an accurate header.
Edge swooped to his left to prevent Mickey Bell making it 3-0 with a low drive and then produced a good stop to keep Peacock out.
But the game had gone off the boil and it took a couple of ankle injuries and replacements to bring some of the bubbles back.
Blackpool lost Danny Coid on half-time after a collision with Rougier and after an hour Bell was stretchered off.
Rougier moved to the left flank to accommodate Scott Murray on the right. It gave City extra width but Blackpool were defending stoutly around Elliott and Mike Flynn.
With a quarter of an hour to go City's dominance was suddenly in peril. Louis Carey brought down Blackpool skipper Richie Wellens just inside the left-hand side of the box.
The penalty award so incensed Carey he talked himself into a booking, the last of four for City.
Keith Southern slammed in the penalty high to the right of Steve Phillips and once again it was game on, with only a great tackle by Danny Coles coming between Mike Sheron and an equaliser.