Erik ten Hag jokes with Ronaldo as Man United train for Europa League - in pictures

It was not the dream return to the starting line-up Cristiano Ronaldo had hoped for, as Manchester United saw their recent winning run come to a frustrating halt against Real Sociedad with a 1-0 defeat at Old Trafford in their Europa League opener.

Having failed to secure a transfer to a Champions League club, the Portuguese striker had to settle for playing in Europe’s second-tier competition for the first time since 2002.

But it was far from smooth even in the lower tier. United pinned Real Sociedad in their own half, with Christian Eriksen finding spaces for Anthony Elanga and Ronaldo but the Spanish team held on with the help their centre-backs.

Ronaldo found the back of the net in the first half, only to see the goal flagged offside. After Eriksen was replaced by Bruno Fernandes for the second half, United lacked creativity and Real Sociedad started to grow in confidence.

They were rewarded in the 59th minute when Brais Mendez converted a controversial penalty after a handball by Lisandro Martinez. The result left United third in Group E, behind Real Sociedad and early leaders Sheriff Tiraspol, who Ten Hag's team face on Thursday.

Ten Hag had used the Portugal star off the bench during the winning streak of four consecutive games in the Premier League. The manager will have a decision to make on Thursday as United return to the football field following the death of Queen Elizabeth II.

United were playing Sociedad at home when Buckingham Palace announced that the nation’s longest-reigning monarch had died at the age of 96. Their next game in the league against Crystal Palace was postponed as a mark of respect for the Queen. United's match against Leeds United this weekend has also been rescheduled because of the