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.
The home fans celebrated wildly while Ole Gunnar Solskjaer was left to reflect on a performance which saw United muster just two shots, the fewest Opta have 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 host Villarreal in their next Group F game on 29 September in a repeat of last season's Europa League final.
Red card & late error cost United
Having spent £120m on three major signings in the summer, United will have hoped to have come away with more than a hard luck tale against the Swiss champions.
But Wan-Bissaka's dismissal - and Lingard's late error - left them reflecting on a seventh defeat in 11 Champions League matches under Solskjaer.
Up until Wan-Bissaka's first red card since 2018, United were in reasonable control and leading after a lovely goal made in Portugal.
Having scored twice on his second debut for United against Newcastle last Saturday, Ronaldo has three goals in two appearances since re-signing from Juventus.
More importantly, the all-time Champions League top scorer now has 135 goals in the competition.
Young Boys keeper David von Ballmoos will feel he should have kept it out, but the pass by Fernandes with the outside of his right foot was simply divine.
Wan-Bissaka's red card prompted Solskjaer to reshuffle his side with expensive summer recruit Jadon Sancho replaced by Diogo Dalot.
Having defended their lead up until half-time, Solskjaer then replaced Donny van de Beek, who was making his first start of the season, with Raphael Varane and switched to five at the back in an attempt to shore up the defence.
It did not work as the home side, full of energy and spurred on by a raucous crowd, eventually made their pressure tell.
After Ngamaleu's equaliser, De Gea was forced to tip Sandro Lauper's 30-yard attempt over the bar before Lingard's attempted pass back fell well short allowing Siebatcheu to earn Young Boys a famous win.
Latest Stories
-
Situate power sector challenges within the context of the 4th Republic – Jantuah
4 mins -
Empowering Youth through IT Education: IT For Youth Ghana College leads the way
11 mins -
Trump criminal case: Full 12-person jury seated in Manhattan
24 mins -
Israel Gaza: US again warns against Rafah offensive
27 mins -
Man arrested in Poland over alleged Russia plot to kill Zelensky
31 mins -
Over 100 arrested as US college Gaza protest cleared
34 mins -
Justmoh Construction begins work on dualization of Takoradi-Agona Nkwanta road
45 mins -
MGL visits Dumor family following passing of Mawuena Trebarh
57 mins -
In Pursuit of Peace and Unity: Interfaith Leaders Promote Dialogue – Chief Doli-Wura to Africa Union
1 hour -
TEWU raises concern over quality of food served in SHS
2 hours -
Ghanaian students gear up for Robotics World Championship
3 hours -
Political interference makes public sector managers appear incompetent – Dr Manteaw
3 hours -
Police arrest truck driver alleged to have caused train crash
3 hours -
CAF Confederation Cup: Dreams FC depart to Cairo ahead of semis first leg against Zamalek
3 hours -
Liverpool exit Europa League despite 1-0 win over Atalanta
3 hours