McQueen was on hand to fire through the massed bodies into the unguarded net.
The young Reds reacted well to going behind, and almost replicated the rapid first-half response, as Ben Pearson fired straight at Wood having been played in well by Barmby. The second equaliser would not be denied for long, though, as James Weir pulled United level with ten minutes to go, striking low into the bottom corner from 20 yards after Andreas Pereira's lay off.
However, Southampton would give United a taste of their own medicine, as the home side regained the lead straight from kick-off. McQueen's run and pass out to Seager found the Saints striker through on goal, and he clipped the ball over Gollini to restore their lead after just 50 seconds of parity.
The home side sealed the win in stoppage time as subsitute Sam Gallagher skipped through United's defence after being played in by Seager, ran past Gollini, and slid the ball past the helpless Pearson on the line.
United: Gollini, Love, Evans (Fletcher 82), Grimshaw, McNair, Pearson, Weir, Daehli, Barmby, Pereira, Harrop (Byrne 55). Subs not used: J.Pereira, McConnell.
This match was shown exclusively live on MUTV. Highlights will also be shown on the channel, at 17:15 GMT on Saturday and 17:00 GMT on Sunday.