Sunderland secured their place in English football's Championship playoffs with a 3-0 win away to Preston on Monday but only after Millwall suffered an extraordinary loss at home to Blackburn Rovers.
The final day of the regular second-tier season kicked off with Millwall knowing a win would guarantee their place in the playoffs that decide the last available spot on offer in next term's lucrative Premier League.
Burnley, the champions, and second-placed Sheffield United were already assured of automatic promotion, but the identity of the clubs finishing fifth and sixth – the teams that would join third-placed Luton and fourth-placed Middlesbrough in the playoffs – had still to be decided.
All seemed set fair for south London club Millwall when they led 3-1 at the interval following two goals from Duncan Watmore and one from Oliver Burke.
But with Joe Rankin-Costello having reduced the deficit, Ben Brereton Diaz's second-half double inspired a Rovers revival at the New Den.
Sunderland's win at Preston, however, meant the northeast side took sixth place, with Blackburn leapfrogging Millwall only to be denied a playoff position of their own on goal difference.
Coventry, meanwhile, claimed a final day point to finish fifth and secure a playoff berth following a 1-1 draw at Middlesbrough – who they will now meet in a two-legged semifinal.