That meant a back five for the second half, with Ronaldo left alone up front, while Young Boys pushed forward looking for an equaliser that came in the 66th minute when Ngamaleu got in front of Varane and prodded home Meschack Elia's cross from the right to the delight of the crowd.
Young Boys had a boisterous support behind them in a packed stadium but United silenced the crowd as they took an early lead, Bruno Fernandes delivering a glorious pass with the outside of his right boot from the left for Ronaldo to steal in behind Ulisses Garcia at the back post and score.
"That's football at the highest level, a lack of concentration, make a mistake and you get punished," Solskjaer said of the mistake that led to the Young Boys winner.
He will be 37 early next year but his hunger for success knows no bounds and he clearly felt returning to Old Trafford gave him a better chance of winning a sixth European Cup than if he stayed at Juventus.
"For a club of our size to make the headlines for one or two days in Europe and to beat Man United, one of the giants of European football, it's really special," said Young Boys coach, David Wagner.
The full-back's studs caught Luxembourg international Martins above the left ankle, and French referee Francois Letexier had no choice but to show a straight red card..Read Full Story