But visiting United lived dangerously from the start.
After 33 minutes, Southampton's Tyler Dibling was fouled by Diogo Dalot, and the referee pointed to the penalty spot. Then goalkeeper André Onana stepped forward and saved Cameron Archer's penalty.
Instead of a home goal, it was 1–0 to United two minutes later.
Bayern München signing Matthijs de Ligt nodded in the lead goal after a corner kick. The Dutchman's first goal in his new club – and a nice revenge after a tough week. The centre-back had a tough time in the Nations League match against Germany and was substituted at halftime.
"Very important"
The first minutes we had problems, but after André (Onana) saved the penalty and after de Ligt's goal, the match was ours, says United coach Erik ten Hag to AFP.
Six minutes later, the lead was extended by another criticized star. Marcus Rashford had not scored for United since March and had also been dropped from the national team. With a well-placed shot, he made it 2–0 from distance and broke his long goal drought.
It's very important for him. For all strikers, it's important to score goals. Now he's made his first, and I'm sure there will be more, says ten Hag.
Captain sent off
In the second half, Southampton's captain Jack Stephens was sent off after a foul tackle on Alejandro Garnacho. In stoppage time, Garnacho then pushed it up to 3–0 in the net. The match's final goal.
United thus bounced back after the stinging 0–3 loss to Liverpool in the previous round. Newcomer Southampton, on the other hand, continues to struggle and has lost all four matches since returning to the top division.