Odsonne Edouard scored twice as Celtic recovered from conceding an early goal to beat Rosenborg in the Champions League second qualifying round.
Birger Meling’s low left-footed shot gave the Norwegian champions a shock lead after 15 minutes.
But record signing Edouard hauled the Scottish champions level just before half-time with a deft touch and finish.
Olivier Ntcham put Celtic ahead from outside the box a minute after the break before Edouard dinked in a third.
Ntcham, Callum McGregor, and Jack Hendry all struck the frame of the goal but Celtic will have to make do with a two-goal lead to take to Trondheim on Wednesday.
Should they emerge unscathed, Brendan Rodgers’ side will then face a third qualifying round meeting with Greek side AEK Athens.
A series of blunders a shock concession
Rosenborg have been having a troubled time of it, with their respected coach Kare Ingebrigsten sacked bizarrely and the players seemingly angry at his departure.
It was an odd preamble for the Norwegians and one that Celtic folk everywhere were hoping would distract and demoralise them ahead of this important first leg.
The reality was that Rosenborg spent the opening 15 minutes looking like a team that had been galvanised rather than dispirited.
Celtic were defensively nervous and might have fallen behind had Mike Jensen managed to get his head on an early cross. It was a warning for Rodgers’ team, but one they did not heed.
Hendry strode out of defence and then proceeded to give the ball away. Rosenborg were ruthless in exploiting his blunder and the ones that followed.
They swept the ball out to Pal Andre Helland, who spun out of a weak challenge by Scott Brown before sliding a ball into Nicklas Bendtner on the left side of the area.
Meling, 40 yards from goal, saw the possibility and darted for the box. Christian Gamboa, carelessly, let him go.
Bendtner picked out Meling and the full-back slipped his shot past Craig Gordon. Beautifully done, but awfully lazy stuff from Celtic.
Rodgers’ switch pays dividends
Rodgers changed things soon enough. James Forrest had been spending a lot of his time playing up front with Edouard drifting wide. Forrest returned to the wing and Celtic started getting men up the field to support Edouard.
Immediately, things got better for the home team. They had what looked like a clear penalty waved away when Ntcham appeared to have a leg taken from under him.
Edouard was to level it before the break, though. Scott Sinclair came in off his left wing and squared to the striker, who took a tidy first touch and then passed his shot into the corner of Andre Hansen’s net.
A goal a few minutes before the break was followed by a goal a few minutes after. What a pearl it was too. Ntcham, in space outside the box, brought the ball on to his right foot and curled a beauty around Hansen to give Celtic a lead they so desperately needed.
They set about trying to add to it. McGregor’s cross came slapping back off the frame of the goal, Edouard’s shot was saved by Hansen, Ntcham’s gorgeous effort from distance was pushed on to the woodwork by the keeper and then Kieran Tierney had a couple of chances inside half a minute.
A Larssonesque way to finish
Celtic stayed patient and stayed dominant and when Rosenborg gifted them possession they made them pay.
Forrest picked it up and put Edouard away. The big man went through one-on-one with Hansen and dinked the most sumptuous chip over his head and into the net for his second and a precious third for Celtic.
A Larssonesque finish from the record signing. Edouard, strong and skilful, looks to be getting better with every game.
There could have been another before the end when Hendry’s effort hit the crossbar. It was the third time that the frame of Hansen’s goal had been rocked.
After their early goal, Rosenborg were hanging on to avoid a scoreline that would have rendered their second-leg task a near impossible one.
Celtic still have a handsome advantage, though. And they have confidence in knowing that they can score again in Trondheim next week.
For Rodgers, a worrying beginning but a pleasing conclusion.
Match ends, Celtic 3, Rosenborg 1.
Second Half ends, Celtic 3, Rosenborg 1.
Birger Meling (Rosenborg) is shown the yellow card for a bad foul.
Substitution, Celtic. Tomas Rogic replaces Olivier Ntcham.
Goal! Celtic 3, Rosenborg 1. Odsonne Edouard (Celtic) right footed shot from the centre of the box to the centre of the goal.
Substitution, Rosenborg. Alex Gersbach replaces Pål Helland.
Olivier Ntcham (Celtic) is shown the yellow card for a bad foul.
Alexander Søderlund (Rosenborg) is shown the yellow card for a bad foul.
Substitution, Rosenborg. Alexander Søderlund replaces Marius Lundemo.
Tore Reginiussen (Rosenborg) is shown the yellow card for a bad foul.
Goal! Celtic 2, Rosenborg 1. Olivier Ntcham (Celtic) right footed shot from the centre of the box to the centre of the goal.
Second Half begins Celtic 1, Rosenborg 1.
First Half ends, Celtic 1, Rosenborg 1.
Goal! Celtic 1, Rosenborg 1. Odsonne Edouard (Celtic) right footed shot from the centre of the box to the centre of the goal.
Scott Brown (Celtic) is shown the yellow card for a bad foul.
Goal! Celtic 0, Rosenborg 1. Birger Meling (Rosenborg) right footed shot from the centre of the box to the high centre of the goal.
First Half begins.
Lineups are announced and players are warming up.