Three late goals from Amad Diallo dragged a below-par Manchester United to an unlikely 3-1 comeback victory over bottom side Southampton in the Premier League on Thursday.

United will have fancied their chances of getting back to winning ways against struggling Saints but the hosts were second best from the off, deservedly falling behind to a Manuel Ugarte own goal just before half-time.

Staring down the barrel of another home defeat, United upped the ante after the break, getting back on level terms through Diallo eight minutes from time, before the Ivorian completed the turnaround in the 90th minute.

A stoppage-time third to complete his hat-trick flattered United, who climbed to 12th in the standings with 26 points from 21 games amid another disappointing season, while Southampton stay on six points and remain 10 adrift of the safety zone.

"In football you have believe," Diallo told TNT Sports. "Very happy to win this. We know we have quality players but we need some times to be more hungry in the final third. Today we showed at the end we were the best team on the pitch."

While there has certainly been recent improvement under new coach Ruben Amorim, United still came into Thursday's encounter looking to avoid a fourth successive home league defeat for the first time since 1934.

Their lack of confidence on the ball was apparent in a poor first half showing. Alejandro Garnacho, making his first league start in over a month, sliced one golden chance well wide but otherwise the visitors were creating the best openings.

A double save from André Onana to deny Southampton's lively Tyler Dibling and then Mateus Fernandes from the rebound was the pick of the United goalkeeper's busy opening period.

The hosts looked like they might get to half-time and regroup but Ugarte's misfortune, with the ball going in off his back from a corner, gave the visitors a deserved lead at the break.

A much-improved United finally started to create more opportunities in the second period, with substitute Antony somehow contriving to miss from close range, but it looked like they would again be frustrated on their own turf.

Then came Diallo's late intervention.

There was an element of fortune about his equaliser, but the 90th minute winner was sublime in its creation from Christian Eriksen and execution before Diallo's first United treble was gift-wrapped by Saints' sloppiness playing out from the back.

Only Wayne Rooney has scored a Premier League hat-trick for United at a younger age (21) than Diallo, who is only the third player in Premier League history to score three times in the final 10 minutes of a game.

A first United win in normal time in seven matches in all competitions was much needed. The performance, however, did little to appease the disgruntled Old Trafford faithful.

"I am from Italy, we are the best in the world in the mentality and the players they are missing in this," Saints manager Ivan Juric said.

"There is a moment you have to be Italian. We are innocent, like kids, playing well and they score. We have to be more evil."