Ole Gunnar Solskjaer will wear a big broad smile when he is back in his office at Old Trafford following his second successive win and 10 out of 12 since he was handed the ephemeral role last year.
Saints Southampton put United on the back foot after Yan Valery unleashed a rasping shot from 30 yards to give them the lead.
But the home side quickly dust themselves up with goals from Andrea Pereira who leveled for the home side, before forward Romelu Lukaku nicked another just seconds before the hour mark.
However, Saints responded just in time with a sublime set piece from James Ward-Prowse that defeated the excellent David De Gea, to bring them back on leveled terms.
Despite efforts to rescue a point away from home, Saints’ hopes were finally dashed with a late winner from Lukaku, sending Manchester United to fourth place, one point atop former holders Arsenal.
Arsenal’s draw at Wembley against Tottenham pushed them one place down to fifth.
Few months ago, United had been cleared off as unserious contenders for the Champions League spot.
But with Solskjaer leading them, they have put to sleep such thoughts. It however remains to be seen if at the end of the season, should they finish well, whether the Norwegian will get the job.