Sunderland secured their place in English football’s Championship play-offs 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 play-offs 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 play-offs — had still to be decided.Amad Diallo for Sunderland during the 2022/23 Championship season:◉ Most goals (13)◉ Most shots (67)◉ Most shots on target (29)└◎ 2nd fouls won (52)└◎ 2nd touches in opp. box (142) └◎ 3rd take-ons completed (62)When loanees become legends… pic.twitter.com/n3dbMz9ghH— Squawka (@Squawka) May 8, 2023 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 play-off position of their own on goal difference.Coventry, meanwhile, claimed a final day point to finish fifth and secure a play-off berth following a 1-1 draw at Middlesbrough — who they will now meet in a two-legged semi-final.EFL CHAMPIONSHIPBirmingham – Sheffield United 1-2 (0-0)/Sanderson 79 – McBburnie 53, McAtee 56/Burnley – Cardiff 3-0 (2-0)/Brownley 27, Barnes 31, Twine 57/Huddersfield – Reading 2-0 (0-0)/Coroma 49, Hungbo 84/Luton – Hull 0-0Middlesbrough – Coventry 1-1 (1-1)/Archer 45+3 – Harmer 22/Millwall – Blackburn 3-4 (3-1)/Vatmur 8, 37, Burk 39 – Varton 22, Rankin Kostelo 51, Dijaz 63, 87/Norwich – Blackpool 0-1 (0-1)/Rodgers 15/Preston – Sunderland 0-3 (0-0)/Diallo 54, Pritchard 61, Clark 65/QRP – Bristol City 0-2 (0-1)/Sykes 28, Bell 56/Swansea – WBA 3-2 (1-1)/Cundle 26, Ntcham 66, Piroe 90+3 – Yokuslu 13, Ajayi 54/Watford – Stoke 2-0 (0-0)/Louza 70, Davies 74/Wigan – Rotherham 0-0