Reading secured promotion to the Premier League with a 1-0 victory at home to Nottingham Forest.
Mikele Leigertwood hooked the ball home from close range in the 81st minute to give the Royals all three points and ensure their promotion. Visitors Nottingham Forest also had cause for celebration on the night as results elsewhere meant they cannot be relegated.
Forest came close to snatching a point and putting the champagne on ice but substitute Marcus Tudgay's header was cleared off the line by Alex Pearce with the striker's follow-up effort being kept out by Adam Federici deep into injury time.
It was Reading's sixth successive win, eighth in a row at home and their 15th in the last 17 games.
Billy Sharp made it 17 goals for the season with a brace as a 3-1 win at Peterborough saw Southampton move five points clear of third-placed West Ham in the automatic promotion race.
Early goals from defender Jos Hooiveld - his seventh of the season - and Sharp set the visitors on their way. Sharp's second all but sealed the points, with a late strike from Tommy Rowe little more than consolation for the home side.
That was after West Ham were forced to settle for a 1-1 draw against a Bristol City side that should now be safe from relegation.
A Robert Green blunder cost the Hammers as the goalkeeper failed to deal with a routine Cole Skuse attempt from range after 29 minutes of a scratchy encounter at Ashton Gate, allowing the ball to bounce up and over his diving body.
Southampton will be certain of promotion if they win either of their two remaining games against Middlesbrough and Coventry, while Bristol City will avoid the drop if they beat either Barnsley or Burnley.
Coventry's future, though, was left hanging by a thread after Shane Lowry's first goal for Millwall saw them go down to a 1-0 defeat in their clash at the Ricoh Arena.
The Sky Blues paid the price after Gary McSheffrey's 56th-minute penalty was saved by veteran goalkeeper Maik Taylor, the clearest of several openings fashioned by the wasteful hosts. Defender Lowry popped up just ten minutes later to head home Alan Dunne's right wing cross and leave City staring at third tier football for the first time since 1964.
Portsmouth's slender chances of staying up remain alive after they clinched three points with a 2-1 win over Crystal Palace.
Scott Allan's deflected effort in the first half, his first goal for the club, and Greg Halford's header after the break gave Michael Appleton's side back-to-back triumphs.
Pompey are now ahead of Coventry on goal difference but both sides remain five points behind Bristol City in the final position of safety.
Angel Martinez's first goal for Blackpool handed Ian Holloway's side a significant victory in their pursuit of a play-off place as they beat Leeds United 1-0.
The former Espanyol midfielder pounced on a loose ball ten minutes from time to sink a spirited Leeds side that finished a man down after Darren O'Dea earned a second yellow card.
Birmingham missed the opportunity to book their place in the play-offs after being held to a 1-1 draw at Ipswich.
A win would have ensured at least a sixth-placed finish for Blues, who were playing their 51st game of the campaign, and they were on their way as Chris Burke's sweet finish in first half injury time put them ahead.
However, Ipswich had been the much better team and, after Daryl Murphy missed a sitter in the first half and Jay Emmanuel-Thomas rattled the crossbar in the second, the former Arsenal striker finally gave his side some just desserts in the 75th minute with a close-range finish.
Goals in either half from Joe Mason and Mark Hudson strengthened Cardiff's grip on the play-offs with a 2-0 victory over Derby at the Cardiff City Stadium.
Despite an encouraging start from Derby, former Plymouth striker Mason gave the Bluebirds a half-time lead with his 11th goal of the season. On the hour, defender Hudson sealed the win with a wonder goal, firing past Frank Fielding from inside his own half to extend Cardiff's unbeaten run to eight league matches.
Will Buckley completed a dramatic Brighton comeback with the equaliser against his former club Watford in a 2-2 draw on the South Coast.
The winger, a £1 million summer capture from Vicarage Road, struck late in the second half as the Seagulls came from two goals behind to snatch a point.
Rising star Sean Murray had put Watford ahead with superb free-kick before Troy Deeney made it two from the penalty spot before half-time, but Inigo Calderon pulled one back and Buckley denied his old side victory while ensuring Brighton avoided a fourth straight defeat.
Relegated Doncaster put the brakes on Middlesbrough's play-off push as they stood firm to earn a goalless draw at the Riverside.
With the pressure off for Doncaster as relegation to League One was confirmed by a home defeat to Portsmouth on Saturday, Rovers showed sparks of the one-touch football that had guided them to the second tier four years ago.
Wins for Cardiff and Blackpool had denied Middlesbrough any possible return to the top six tonight, and their profligacy may come back to haunt them with just two more matches remaining this term.
Matty Fryatt's hat-trick secured a 3-1 victory that kept Hull in with a mathematical chance of reaching the play-offs while Barnsley can finally put their relegation fears to bed despite an eighth defeat in ten matches.
Former Leicester striker Fryatt took his tally for the season to 15 with two close-range strikes in the first half followed by a superb solo goal late in the game.
Nick Barmby's side could still catch Blackpool or Cardiff if they win their last two matches and either one of those two teams fails to take another point. However, both have a superior goal difference over the Tigers, who also trail sixth-placed Middlesbrough by two points.
Burnley were denied a club record-equalling 11th away league win by a huge slice of misfortune as they drew 0-0 at Leicester. Both sides created chances to score but Charlie Austin came closest to breaking the deadlock just before the hour mark when he saw a header strike both posts.