Cristiano Ronaldo scored a first-half goal for Manchester United in their opening game of the 2021/2022 UEFA Champions League campaign.
The Portuguese international needed just 13 minutes to score his third goal for Red Devils since joining from Juventus.
United was reduced to 10-men after right back Wan-Bissaka was issued a straight red card on the 36th minute.
Young Boys came back stronger in the second half with Ngameleu grabbing an equalizer on 66 minutes.
The Swiss side left it late to grab a winner as substitute Theoson Siebatcheu scored on added time to spoil a second Champions League debut for Cristiano Ronaldo.