Bruno Fernandes volleyed home a cross from Diogo Dalot in the 55th minute to propel United from 14th position to sixth place in the league table.
Ten Hag opted for a mostly-unchanged lineup from the eleven that started in Monday’s 2-1 win against Liverpool. Scott McTominay starting in place of Fred in the midfield was the only change made.
United didn’t start the match with the same intensity as they did against Liverpool earlier in the week, but they managed to get the job done.
The majority of the attacking chances throughout the 90 minutes came from the right wing, with the play usually stemming from Christian Eriksen to Diogo Dalot, who would cross the ball for one of the forwards to attack.
The Portuguese right-back spurred multiple scoring opportunities in the opening 20 minutes, starting with a cross into Bruno Fernandes that was just a bit too high for his compatriot to get his head on in the 10th minute.
United looked destined to score in the 19th minute when Dalot then played another cross from the top of the box into Fernandes, whose header from the six-yard box was blocked. The ball rebounded to Anthony Elanga on the other side of the six, but his shot was blocked as well, which led to a volley and a shot by Eriksen get blocked as well in a series of seconds.
There wasn’t much other notable attacking action from United in the first half, as it looked like ten Hag might have needed to change something within the front three of Jadon Sancho, Marcus Rashford, and Elanga to generate more chances.
However, United’s back four of Tyrell Malacia, Lisandro Martínez, Raphael Varane, and Dalot was once again stellar throughout the match, producing another impressive performance that, together with David de Gea, earned a clean sheet.
United started the second half with more energy to get forward and created two scoring chances within six minutes. Elanga, who struggled to generate much on the right wing in the first half, was part of the build-up in both chances to start the half.
The 20-year-old Swede also played a role in the build-up to Fernandes’ winner. Elanga carried the ball into the midfield and played the ball to Sancho, who sent the ball out wide to Dalot to whip into Fernandes. The Portuguese midfielder placed his shot out of goalkeeper Gavin Bazunu’s reach in the bottom left corner.
Cristiano Ronaldo replaced Sancho in the 68th minute, but the match wasn’t the right kind of game to play into Portuguese superstar forward’s strengths. Rashford, who played as the center forward prior to Ronaldo being introduced, did not see much of the ball either.
New signing Casemiro made his United debut as he replaced Elanga ten minutes later, and Fred came on in stoppage time for Eriksen.
Southampton had a late chance to try to force a draw, but Dalot found himself in the right position to block the shot and thwart the danger.
Despite it not being United’s best attacking performance, ten Hag earned his second win in England’s top flight and will continue to build from here and develop his system. One or two more signings by the end of the transfer window could certainly help strengthen his side which looks to be improving each day.