A ruling in a Swiss court and the concession of a late, late goal in the Premier League ensured a Champions League qualification place remained tantalisingly out of reach for Manchester United.
The Red Devils blew a chance to return to the top four of the league for the first time since September when Southampton substitute Michael Obafemi scored in the sixth minute of stoppage time to secure a 2-2 draw at Old Trafford on Monday.
It was the latest twist in a turbulent race for Champions League qualification, coming on the day second-placed Manchester City had their two-year ban from European competition overturned by the Court of Arbitration for Sport.
That means a finish in the top four is required to join Europe's elite next season.
Obafemi's dramatic close-range strike from a corner kept United in fifth place - behind Leicester City only on goal difference with three games remaining with Chelsea one point ahead in third place.
On the final day of the season, Leicester host United in what could be a lucrative, winner-takes-all match.
United manager Ole Gunnar Solskjaer admitted Southampton were worthy of heading back to the south coast with a point.
"You just have to be strong and take it," he said of the gut-punch that denied his team a fifth-straight victory.
"Because we have won so many games like that ourselves.
"We probably didn't deserve three points today."
The match went so deep into added-on time only after a facial injury to substitute Brandon Williams, which left United with 10 men for the final three minutes because Solskjaer had used all five of his replacements.
United had enough chances to win a game in which they fell behind in the 12th minute, when Stuart Armstrong scored.
Two goals from United in a three-minute span turned things around.
Marcus Rashford netted a 20th-minute equaliser before Anthony Martial scored his 50th Premier League goal to give the hosts the lead.
Solskjaer fielded the same starting line-up for the fifth game in a row and is likely to freshen things up for the match against Crystal Palace on Thursday - with Luke Shaw in doubt through injury.
Australian Associated Press
