Coventry City and Sunderland have secured the final two Championship playoff places on Monday afternoon.
While Coventry went into the final day sitting in fifth spot in the table, it was seventh-placed Sunderland who had the least eventful afternoon.
The Black Cats scored three times during the first 20 minutes of the second half at Preston North End, Amad Diallo, Alex Pritchard and Jack Clarke all getting on the scoresheet.
That effectively left Millwall needing all three points at home to Blackburn Rovers in a game which they held a 3-1 half-time advantage.
However, Joe Rankin-Costello and a double from Ben Brereton Diaz earned the visitors a remarkable 4-3 win, one which ultimately proved not enough to earn a top-six place.
As a result of that unforeseen comeback, Coventry City only needed a point at Middlesbrough, and the Sky Blues held on for a 1-1 draw during the second half to end the regular campaign.
Those scorelines meant that West Bromwich Albion were unable to snatch sixth place regardless of the outcome versus Swansea City in South Wales.
Nevertheless, the Baggies went down by a 3-2 scoreline, despite twice leading that contest, and they have to settle for ninth position.
Meanwhile, champions Burnley ended the season with 101 points as they cruised to a 3-0 success over Cardiff City.
