Manchester United sensationally lost 2-1 to Swiss underdogs Young Boys despite Cristiano Ronaldo scoring on his Champions League return for the Red Devils.
Ronaldo, who became the joint all-time Champions League appearance holder on his 177th appearance in the competition, fired United ahead after an exquisite pass from fellow Portuguese Bruno Fernandes.
United played for almost an hour with 10 men after Aaron Wan-Bissaka’s dangerous challenge on Christopher Martins earned the defender a straight red card.
They looked set to hang on for a point in an entertaining match after Cameroon winger Moumi Ngamaleu’s equaliser.
But a 95th-minute mistake by substitute Jesse Lingard – who had replaced Ronaldo with 19 minutes left – allowed Jordan Siebatcheu to score the winner for the Swiss.
The home fans celebrated wildly while Ole Gunnar Solskjaer was left to reflect on what could have been after their flying start.