Late goals from Danny Webber and Phil Bardsley sealed victory for the Red Devils in what was a thoroughly entertaining contest during the international break.
Saints threw it back to their League One days as Rickie Lambert and Lee Barnard reformed their formidable strike partnership one more time.
Jo Tessem and Andrew Surman partnered Victor Wanyama in the middle, as the Kenyan turned out in Saints colours for the first time in nearly a decade.
Supporters and autograph hunters flocked to the United bench before kick-off, hoping to get an item or two signed by a Red Devils legend.
And who could blame them as United brought a side full of champions, and their attacking line, which included Louis Saha, Antonio Valencia and Dimitar Berbatov, promised to entertain.
They nearly combined to open the scoring when Valencia broke down the wing to set up a chance, which Berbatov hit onto the post.
Wanyama was urged to shoot any time he got within 40 yards of goal; those in attendance clearly hoping to see another screamer from the 34 year old.
The tough task of keeping Valencia quiet down the right wing fell on the shoulders of Franny Benali, and he had to clear off the line after the Ecuadorian beat him for pace.
That goal-line intervention was a launch point for Saints to take the lead. They worked the ball out to Andrew Surman, who, in turn, found the clinical boot of Barnard.
Under-18s boss Surman nearly doubled the lead when his well-hit low effort from the edge of the box skipped past the post.
The game slowed down as the first half progressed, and a late, tight-angle Tommy Forecast save looked good to have Saints level at the break.
But retired full-back Phil Bardsley had other ideas and found the bottom corner, to tongue-in-cheek boos, right before the break.
United made good on that goal and doubled their lead within minutes of the restart when Campbell punished Forecast’s loose attempt to gather a cross.
The game degenerated into a goal fest from there. Saints were soon level when Lambert tapped in from close range in front of the Northam End.
The game did not stay level for long. Campbell got his second, powering through the hands of Forecast, who made up for that error minutes later.
After Wanyama was adjudged to have fouled Berbatov inside the box, the Bulgarian forward stepped up and sent a tame penalty straight at the Saints stopper.
Barnard joined Campbell on a brace by tapping into a vacant net with 20 minutes to go, setting up a grandstand finish at St Mary’s.
Matt Le Tisser entered to rapturous cheers with 10 minutes to go, aiming to score the winner, yet found his side behind less than a minute later.
Ken Monkou and Mark Blake were unable to close down United’s forward quickly enough, and Danny Webber restored the visitors’ lead with a simple close-range finish.
Matt Le Tissier on for the final 10-ish minutes and gets the armband from Rickie Lambert. #SaintsFC pic.twitter.com/q2wwG9wj7Z
— George Rees-Julian (@rees_julian) March 28, 2026
Bardsley got his second of the afternoon in the dying moments to make double sure United’s legends left with the bragging rights.
Saints: Forecast, Richardson, Hooiveld, Svensson, Benali, Surman, Wanyama, Tessem, Pele, Lambert, Barnard.
Subs: Blake, Le Tissier, Cockerill, Monkou, Hughes, Forbes, McQueen.
Man United: Raimond van der Gouw, Bardsley, Johnsen, Brown, Simpson, Gibson, Djemba-Djemba, Valencia, Saha, Webber, Berbatov.
Subs: Djordjic, Pugh, Campbell, Piklington.