Manchester United remain in fifth spot in the Premier League after dropping points against Southampton on Monday night.
For the fifth successive encounter, the Red Devils showed up with an unchanged starting eleven following five straight victories in the league too.
United missed a glorious opening off a poor back-pass from James Ward-Prowse nine minutes in, as Anthony Martial failed to get the better of Alex McCarthy.
The Saints stunned their more illustrious opponents when Stuart Armstrong controlled a cross from the left before drilling into the far corner three minutes later.
Marcus Rashford clawed the home side level 20 minutes gone with a first-time finish from the far post following a lay-off from Martial.
Martial then got himself on the score-sheet when he ran in from the left before finding the top corner two minutes later, which was similar to his goal against Bournemouth last week.
The Frenchman could’ve had a brace nine minutes before halftime, but he dragged his effort horribly over the top following a cut-back on the edge of the area by Paul Pogba.
Rashford looked for a second and the side’s third ten minutes after the restart, but flashed into the side-netting from the bottom-left area.
The first change of the evening for the home side saw Pogba making way for Brazilian Fred with 60 minutes played, as United looked to hang onto the result.
Southampton pushed for a positive ending in the remaining minutes, and found their just rewards deep in stoppage time when Michael Obafemi fired home from close-range from James Ward-Prowse's corner.
The result leaves the race for the top-four wide open, with United failing to climb into the top-four bracket following defeats to Chelsea and Leicester City over the weekend.