Peterborough threw away the chance to secure automatic promotion from League One after squandering a two-goal lead in a 2-2 draw at home to Doncaster.
A win would have secured a return to the Sky Bet Championship after an eight-season absence and they appeared on course as Joe Ward and Sammie Szmodics put them in control midway through the first half.
However, Fejiri Okenabirhie's low strike pulled one back before the interval and Taylor Richards' close-range finish left Posh boss Darren Ferguson fuming.
It left Peterborough needing a point in their penultimate game at home to Lincoln - the only side who can now catch them - to make certain.
The Imps capitalised on Sunderland's 1-0 defeat at Blackpool - who strengthened their play-off position thanks to Sullay Kaikai smashing home from 20 yards - to move into third with Jorge Grant's 11th-minute goal enough to beat Shrewsbury.
Portsmouth's John Marquis had a roller-coaster finish to the match at Accrington as he thought his volley in added time had won the game only for goalkeeper Clan MacGillivray's save at the other end to rebound off the striker and go in for an own-goal equaliser in the time added on for Pompey's celebrations as the match ended 3-3.
Colby Bishop and Cameron Burgess had given Stanley a 2-0 half-time lead but Marquis and Ryan Williams levelled things up early in the second half with the eventual point lifting Portsmouth into the final play-off place.
At the other end of the table, Rochdale's survival hopes were dealt a cruel late blow as they conceded in the seventh minute of added time to draw 3-3 at AFC Wimbledon.
Dale had led 2-0 with just over half-an-hour to go through Jake Beesley and Gabriel Osho only for Jack Rudoni and Ollie Palmer to level things up with goals just five minutes apart.
Jimmy Keohane's header - followed by goalkeeper Jay Lynch saving Joe Piggott's 84th-minute penalty - looked to have put the visitors within two points of safety and drag Wigan closer to the drop zone only for Pigott to redeem himself with virtually the last kick and keep his side from being sucked into the battle.
A late Crewe equaliser dealt a blow to Charlton's promotion hopes as Owen Dale's second of the match in the sixth minute of added time snatched a point and denied the hosts the chance to draw level with sixth-placed Portsmouth.
Jayden Stockley and Alex Gilbey had twice put Charlton ahead, the latter's coming seven minutes from the end, but Dale struck later.
Burton beat Fleetwood 5-2 in their mid-table encounter with Kane Hemmings leading the scoring for the hosts with two, with Lucas Akins, Joe Powell and Thomas Hamer also on the scoresheet as Sam Finley and Jordan Rossiter briefly made it 2-1 and 4-2.
Sky Bet League Two
Cheltenham secured promotion from Sky Bet League Two following a 1-1 draw with Carlisle, while Grimsby were relegated after conceding two late goals to lose 3-2 at Exeter.
Chris Hussey's stunning 56th-minute free-kick guaranteed the table-topping Robins would return to League One for the first time since 2009 after Joshua Kayode put the visitors ahead in the first half.
Celebrations for Michael Duff's men were almost put on hold but a late header from Kayode crashed against the crossbar.
At Exeter, it was an evening to forget for 10-man Grimsby as a dramatic collapse condemned them to a 3-2 defeat - and relegation
Lenell John-Lewis's penalty and Jay Matete's strike from distance turned the game in their favour after Luke Waterfall's own goal put the play-off-chasing Grecians ahead.
But, after Matete was dismissed for a reckless challenge on Archie Collins, goals in the final eight minutes from Alex Fisher and Ryan Bowman ensured the Mariners would return to the National League following a five-season stay in the fourth tier.
Newport boosted their play-off hopes thanks to a thumping 4-0 success over lowly Scunthorpe.
George Taft's own goal, Mickey Demetriou's double and a strike from Lewis Collins lifted the Exiles to sixth, while the Iron still require a single point to mathematically stave off relegation.
Salford are a place below Newport after snatching a late win at Bradford. Ammies leading scorer Ian Henderson struck in stoppage time at Valley Parade to steal a 1-0 success for Gary Bowyer's men.
Elsewhere, Barrow guaranteed their safety with a 2-0 victory which dented Forest Green's promotion hopes.
Joe Quigley's penalty and a close-range Bobby Thomas strike moved the Bluebirds eight points clear of the bottom two while the beaten hosts' dropped to eighth, a point outside the play-off spots.