London: Southampton blew a chance to clinch promotion to the Premier League as Middlesbrough came from behind to win 2-1 at the Riverside Stadium.
Nigel Adkins` second-placed side would have opened up an unassailable eight-point lead over promotion rivals West Ham United if they had won on Teesside on Saturday.
But, despite taking the lead through Billy Sharp`s strike just 46 seconds into the match, the Saints allowed Middlesbrough to take the points thanks to Nicky Bailey`s equaliser and Merouane Zemmama`s late winner.
Southampton -- five points clear of West Ham -- will now be keeping a keen eye on the Hammers` trip to Leicester City on Monday, when a defeat or draw for the east London club would seal promotion for Adkins` men.
Zemmama`s goal kept Tony Mowbray`s side in the hunt for the play-off places as they lie two points behind Cardiff City with one game to play.
Southampton had made the perfect start when Adam Lallana cushioned a header into the path of Rickie Lambert, who laid off for Sharp to fire home.
Middlesbrough drew level in first half stoppage-time. Barry Robson`s cross was headed out into the path of Bailey, who let fly with a volley that deflected in off Richard Chaplow.
Adkins` team pressed for a winner but it was Middlesbrough who stole the points in the 77th minute.
Jose Fonte was penalised for holding back Lukas Jutkiewicz and from the resulting free-kick, Zemmama curled a beautiful shot into the top corner.
Reading, fresh from sealing promotion in mid-week, were held to a 2-2 draw by Crystal Palace at the Madejski Stadium but still clinched the Championship title thanks to Southampton`s defeat.
Brian McDermott`s side had Jason Roberts sent off on the stroke of half-time with the score at 1-1 after Wilfried Zaha`s 14th-minute strike and a swift equaliser from Reading defender Kaspars Gorkss.
The Royals moved in front through Adam Le Fondre`s second-half goal but were pegged back by Glenn Murray`s 74th-minute leveller.
At the other end of the table, Portsmouth and Coventry City were both relegated to League One alongside Doncaster Rovers, whose fate had already been sealed.
Portsmouth were deducted 10 points for going into administration earlier this season and that punishment proved decisive as seven points separated them from safety with one game remaining.
The south-coast club -- FA Cup winners as recently as 2008 -- were beaten 2-1 at home by Derby County, but even a win would not have been enough to avoid demotion to the third tier for the first time since 1983 after relegation rivals Bristol City beat Barnsley 2-0.
Coventry`s last hopes of survival were ended by a 2-0 defeat against Doncaster at the Ricoh Arena.
James Hayter converted an 81st-minute penalty for Rovers following Richard Keogh`s red card and Simon Gillett netted just before the end to leave Coventry facing third-tier action for the first time since 1964.
Meanwhile, Blackpool confirmed their play-off place with a 4-0 win over Burnley, while Birmingham City are all but certain to join the Seasiders in the top six after a 1-1 draw at Brighton.
Cardiff dropped to sixth after a 1-1 home draw against Leeds United, but Middlesbrough`s draw means the League Cup runners-up are assured of a play-off spot.
Elsewhere, Hull City defeated Nottingham Forest 2-1, Millwall routed Ipswich Town 3-0 at Portman Road and Peterborough United drew 2-2 with Watford.