Match ends, Young Boys 2, Rangers 1.
Rangers had top spot in their Europa League group ripped from them inside stoppage time after Christian Fassnacht snatched a late winner for Young Boys.
Two errors by James Tavernier cost Steven Gerrard's side, who led through Alfredo Morelos and had the better chances against the Swiss champions.
First, Tavernier lost possession near his own corner flag in the lead up to Roger Assale's leveller, then the captain's slip allowed Fassnacht to burst forward and scud a 93rd-minute winner past Allan McGregor.
Feyenoord's victory over Porto in Rotterdam means all four teams in Group G now have three points from their opening two games.
Rangers now face a double header against Porto, travelling to face the group favourites in Portugal in three weeks' time.
Young Boys have last laugh
For 93 minutes of this contest, it appeared Rangers had delivered another accomplished performance in keeping with their ongoing development in continental combat. Prior to this defeat, Gerrard had lost just twice in 23 Europa League games and for large swathes in Bern, that experience was evident.
They were defensively unflustered, disciplined in midfield, and sporadically menacing in attack against a side who were only denied a Champions League group stage place by Red Star Belgrade on away goals.
Morelos' opener was ample reward for an unfussy first-half performance. The Colombian striker had earlier scuffed a tame effort straight at goalkeeper David von Ballmoos after scuttling on to a Borna Barisic pass into the left channel, but he was much more clinical when a near-identical opportunity came again. This time, the 23-year-old barrelled after the ball, bounced Frederik Sorensen aside, and advanced into the box before whipping a clinical finish across Von Ballmoos.
It was his ninth European goal this season and a 13th in 25 Europa League games for a Rangers side who were suddenly in command of an even contest. Indeed, they might even have doubled their interval lead had Sheyi Ojo not slashed an an effort across the face of goal just before the whistle.
Young Boys, who had lost their opener in Porto, had previously gone 24 games unbeaten at the Stade de Suisse and had lost just once in 14 this term. It was only to be expected, then, that they would be roused after the interval and it took them just five minutes to restore parity en route to reviving their Group G ambitions.
Tavernier was caught on the ball near his own corner flag and, when Ulisses Garcia flashed a delivery across the face of goal, Assale took advantage of Filip Helander being unable to intercept by thrusting out a leg to divert into the net.
With Rangers having opted not to take up their ticket allocation in response to a second Uefa charge for sectarian singing, only a pocket of their fans had managed to find their way into the ground. They were drowned out by a home support enlivened by the goal, but the change in atmosphere did not unduly affect the visitors.
Indeed, it was Rangers who continued to cleave the better openings. A ferocious Morelos lash from the right apex of the area was unconvincingly shovelled over by Von Ballmoos, then the Colombian might have had a penalty after appearing to be caught by Garcia at the back post. The striker then had one more chance, only to see his fierce deflected effort pushed away by Von Ballmoos.
Still, a point would have been a valuable prize after the opening win over Feyenoord and that looked the most likely outcome as the game neared a conclusion.
However, when a clearing Helander header was redirected back towards the Rangers defence, Tavernier lost his footing as he tried to clear, allowing Fassnacht to stride forward and fizz a low strike past McGregor. Within a few seconds, Gerrard's side had gone from topping the group to wondering what had gone wrong.
Man of the match - Steven Davis
BBC Scotland's Brian McLauchlin at Stade de Suisse
This was a harsh lesson for Steven Gerard and his players. Not only should they not have lost, but they could easily have taken all three points and set themselves up for the rest of the campaign.
They can look at the mistakes by Tavernier, which handed the Swiss champions the victory, but Rangers certainly showed enough on the night to suggest that, if they can eradicate their errors, progress in the competition is well within their grasp.
On a night when few Rangers players stood out, the the experience of Steven Davis was evident. Now a veteran, he played a major part in setting up Morelos for his goal and he will feel hard done by finishing up on the losing side.
- Young Boys have ended Rangers' nine game unbeaten run on the road across all competitions (W7 D3 L0 previously)
- The Swiss have won 13 of their previous 18 home matches in the Europa League (D1 L4), winning their last two contests after conceding first
- Rangers are winless in their last 13 group games away from home since beating Sporting 2-0 in the Uefa Cup in April 2008
- Morelos has scored 14 goals in his 18 games for Rangers in all competitions this season
- 26von Ballmoos
- 3SörensenBooked at 52mins
- 5ZesigerBooked at 87mins
- 11GaudinoSubstituted forMoumi Ngamaleuat 73'minutes
- 17AssaléSubstituted forLotombaat 67'minutes
- 13Moumi Ngamaleu
- 2TavernierBooked at 90mins
- 10DavisBooked at 90mins
- 8JackSubstituted forStewartat 65'minutes
- 20MorelosBooked at 89mins
- Manuel Schüttengruber
- Shots on Target
Second Half ends, Young Boys 2, Rangers 1.
Goal! Young Boys 2, Rangers 1. Christian Fassnacht (Young Boys) left footed shot from outside the box to the bottom left corner. Assisted by Cédric Zesiger with a headed pass.
Offside, Rangers. James Tavernier tries a through ball, but Connor Goldson is caught offside.
Alfredo Morelos (Rangers) wins a free kick in the attacking half.
Foul by Fabian Lustenberger (Young Boys).
Steven Davis (Rangers) is shown the yellow card.
James Tavernier (Rangers) is shown the yellow card for a bad foul.
Foul by James Tavernier (Rangers).
Nicolas Moumi Ngamaleu (Young Boys) wins a free kick on the left wing.
Corner, Rangers. Conceded by David von Ballmoos.
Attempt saved. Alfredo Morelos (Rangers) left footed shot from outside the box is saved in the top left corner. Assisted by Greg Stewart.
Alfredo Morelos (Rangers) is shown the yellow card for a bad foul.
Foul by Alfredo Morelos (Rangers).
Fabian Lustenberger (Young Boys) wins a free kick in the defensive half.
Cédric Zesiger (Young Boys) is shown the yellow card for a bad foul.
Offside, Rangers. Alfredo Morelos tries a through ball, but James Tavernier is caught offside.
Attempt saved. Frederik Sörensen (Young Boys) header from a difficult angle on the right is saved in the bottom right corner. Assisted by Michel Aebischer.
Michel Aebischer (Young Boys) wins a free kick in the attacking half.
Foul by Greg Stewart (Rangers).