Manchester United conceded a dramatic stoppage-time goal as they lost to 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 18 minutes left – allowed Jordan Siebatcheu to score the winner for the team that had to come through qualifying to reach the group stage.
The home fans celebrated wildly while Ole Gunnar Solskjaer was left to reflect on a performance that saw United muster just two shots, the fewest Opta has on record in any of their 138 Champions League matches since 2003-04.
Having missed out on qualifying for the knockout stages of the competition last season, United now hosts Villarreal in their next Group F game on 29 September in a repeat of last season’s Europa League final.