Southampton took an early lead but slipped behind thanks to a five-minute blitz in the second-half before Ward-Prowse's leveller and Lukaku's late winner
ROMELU LUKAKU made it four in a week to shoot United back into the Champions League slots on a dramatic afternoon.
The Belgian, who bagged a double at Palace on Wednesday, helped himself to another two here.
And his second, a magnificent right footed winner two minutes from time, was enough to finally kill off scrapping Saints.
Jack Ward-Prowse’s magical long range free kick had given the relegation fighters a 74th-minute equaliser which seemed certain to keep United in fifth place.
But the Lukaku let one roll across his body and unleashed a curling drive into the far corner to keep the Ole Gunnar Solskjaer roadshow rumbling along.
Yan Valery had set the tone with his thunderous effort on 25 minutes to open the scoring, even though David De Gea got a hand to it.
Then Brazilian youngster Andreas Pereira struck his first Premier League goal for United to tie it up early in the second half, curling into the top corner also from 25 yards.
It looked like being a day to remember for Pereira, given the nod ahead of fellow countryman Fred in midfield, when his ball to Romelu Lukaku saw the Belgian shoot United in front just before the hour.
The points could – probably would – have been wrapped up if Diogo Dalot’s daisycutter of a drive had been a yard to the right, rather than fizzing just wide.
Ward-Prowse certainly made the most of it when Ashley Young was pulled up for a foul on Stuart Armstrong outside the box, whipping one over the wall and into the corner.
United certainly had enough chances to have sealed it even before Valery’s opener, let alone Ward-Prowse’s equaliser, yet Angus Gunn was in sparkling form.
The Saints keeper started with a stunning low save to keep out Lukaku’s drive, and then came up with another impressive tip over from Alexis Sanchez.
And he made it a hat-trick of fine stops with a point blank block to deny Lukaku again after Chris Smalling’s nod down.
That seemed certain to put the brakes on the United express – but their giant Belgian striker had other ideas, which even afforded them the luxury of a missed spot kick from Paul Pogba with virtually the final kick.
