Sunderland sneaked into the Championship play-offs thanks to a crushing victory over Preston North End and Millwall's astonishing 4-3 defeat against Blackburn Rovers.
The Black Cats needed maximum points and for other results to go their way on the final day and, in a bewildering climax to the regular season, Tony Mowbray's side kept their part of the bargain in style as spectacular second-half strikes from Amad Diallo, Alex Pritchard and Jack Clarke saw them romp to victory.
Coventry City booked the other slot thanks to a 1-1 draw away against already play-off bound Middlesbrough, but Millwall squandered a 3-1 advantage at home against fellow hopefuls Blackburn, meaning they missed out to the Black Cats by a point.
Sunderland will face Luton Town in the play-offs, with the first leg at the Stadium of Light on Saturday, 13 May and the return meeting on Tuesday, 16 May.
Preston began the day embracing their role as potential party-poopers, getting on top early on and almost going ahead when a fierce Ali McCann strike was deflected just a fraction wide with keeper Anthony Patterson well beaten.
The visitors, who were looking to extend their unbeaten run to nine games despite a lengthy injury list, soon settled, having strong shouts for a penalty following a clumsy challenge by Patrick Bauer on Joe Gelhardt waved away.
And then only a brilliant one-handed save by keeper Freddie Woodman prevented a Patrick Roberts strike from arrowing its way into the top corner. Woodman also made an equally fine sprawling stop from Gelhardt after a glorious flowing move.
Preston remained dangerous in an enthralling tussle played in the intermittent Lancashire rain, on-loan Manchester City forward Liam Delap sending a low shot just off target after racing through one-on-one and Tom Cannon headed straight at Patterson from eight yards.
But an increasingly confident Sunderland were were playing with typical verve and freedom despite their desperate need for a goal, and the pressure and quality finally told in a one-sided second period.
After Dan Neil sent a measured shot a whisker away from nestling in the bottom corner and Woodman spread himself to block Pierre Ekwah's close-range shot, Sunderland deservedly went ahead through Manchester United loanee Diallo's stunning curled effort from the edge of the box.
Substitute Pritchard soon made it 2-0 with another delightful effort from distance, cleverly deceiving Woodman with a beautifully disguised strike with his instep.
And a third goal in 11 minutes sealed the points, Clarke getting on the end of yet another stunning counter-attack, cutting inside and placing his shot into the bottom corner from 18 yards.
By now Millwall had been pegged back to 3-3 and news then filtered through to Sunderland's already large and buoyant away support that the Lions' hopes of victory had vanished with Ben Brereton Diaz's late strike putting Rovers ahead.
The thrilling comeback in south east London meant Millwall - who started the day in sixth - dropped to eighth as Sunderland moved above them, with Rovers finishing seventh on goal difference.