Boss Ian Holloway knew only three points would give Blackpool a realistic chance of survival amid the dramatic twists and turns of the final day of the campaign, as five clubs fought to secure Premier League status.
And when goals from Charlie Adam and Gary Taylor-Fletcher turned around an early deficit into a 2-1 lead at Old Trafford, the Tangerines looked on course to navigate an unlikely path to survival at the home of the newly-crowned champions, who have lost only two points at home all season.
Sadly for Holloway, his players and the thousands of Blackpool supporters who travelled in hope of an escape, Man United scored three times in the final 30 minutes.
Birmingham were relegated to the Championship after they lost 1-2 at Tottenham, with Roman Pavlyuchenko's late goal for Tottenham clinching victory for the home side.
Early on results elsewhere were going City's way, and Birmingham seemed safe when Craig Gardner equalised mid-way through the second half after substitute Pavlyuchenko had given Tottenham the lead.
But Wolves' second goal in their 2-3 defeat by Blackburn put Birmingham City back in the bottom three, and Pavlyuchenko's last-minute strike confirmed the Blues' fate.
Pos Team Pl GD Pts
16 Wigan 38 -21 42
17 Wolves 38 -20 40
18 Birmingham 38 -21 39
19 Blackpool 38 -23 39
20 West Ham 38 -27 33