Romelu Lukaku scored his sixth Premier League goal of the season to give Manchester United a hard-fought victory at Southampton.
Lukaku broke the deadlock on 20 minutes, converting the rebound after Saints goalkeeper Fraser Forster parried his header from Ashley Young’s cross.
The result maintains United’s unbeaten start to their league campaign, although they are second in the table, behind Manchester City on goal difference.
Their latest victory was not routine as Southampton piled on the pressure in the second half, and United’s Marouane Fellaini had to clear Oriol Romeu’s header off the line.
Mauricio Pellegrino’s side enjoyed 70 per cent of the possession in the second half but struggled to find a way through United’s rearguard, underlining the attacking problems of a team who have failed to score in nine of their last 11 home league games.
United move on to 16 points, the same as league leaders City, but Mourinho will no doubt want improvement from his side when they travel to Russia to take on CSKA Moscow in the Champions League on Wednesday.
United, who have only conceded two goals in six league games so far this season, ended the game with six defenders on the pitch as Mourinho brought on Chris Smalling and Daley Blind to hold on to the points.
Southampton had chances – Romeu’s header beat David de Gea but Fellaini was well placed to clear it off the line, before the excellent Romeu shot narrowly wide from a tight angle.
Nathan Redmond also had a shot saved by De Gea, and not even the second-half introduction of forwards Manolo Gabbiadini and Charlie Austin could unsettle United’s defence.
Southampton have scored only four league goals this season, but manager Mauricio Pellegrino can take huge encouragement from their second-half performance.
– Sixteen points from their opening six games is Manchester United’s best start to a Premier League season since 2011-12.
– Southampton have failed to score in eight of their last nine home Premier League games, with their 3-2 win against West Ham this season the exception.
– Romelu Lukaku has scored six goals in his six Premier League games this season – Louis Saha is the only other player to have scored as many goals in his first six games for United in the competition.
– Southampton have lost 11 Premier League games in 2017 – as many as they had lost in 2016, with 15 matches still to play this year.