Brendan Rodgers saw his faith in the goalscoring potential of James Forrest spectacularly vindicated as the winger’s thunderous strike took Celtic into the play-off round of the Champions League.
Forrest scored the only goal of a nervy third qualifying round tie with just over 20 minutes remaining, its timing perfect just as Rosenborg appeared to be seizing control and threatening to hand Rodgers a significant setback.
Thanks to Forrest’s moment of magic, the Celtic manager remains on course to lead his team into the Champions League group stage for the second successive season. At the very least, the Scottish champions are now guaranteed European football until Christmas as they would drop into the group stage of the Europa League if they lose their final qualifier.
Their sights will be firmly focused on the bigger prize, however, having emerged unscathed from a tie in which they were, for the most part, without the services of both central strikers Moussa Dembele and Leigh Griffiths.
It was an evening of high stakes and big decisions for Rodgers. He opted to begin with fit again Griffiths on the bench, handing Forrest the responsibility of spearheading the pursuit of an away goal.
The other significant choice was at the back where Erik Sviatchenko was restored in central defence at the expense of Kristoffer Ajer who was not even named among the substitutes. That selection backfired when Sviatchenko succumbed to injury yet again with less than half an hour played, limping off to be replaced by Israeli international midfielder Nir Bitton.
Despite that disruption to their plans, Celtic were generally the more progressive side and certainly created the better chances in a first half which provided goalkeeper Craig Gordon with little cause for concern.
He did have to make the first save of the match, comfortably holding a snapshot from Milan Jevtovic after some sharp play from Rosenborg’s captain and most accomplished player Mike Jensen.
But Celtic looked by far the more likely side to make a breakthrough and Mikael Lustig might have done better against his former club when, left unmarked and picked out by a Kieran Tierney cross, he blazed his shot wildly over.
Celtic came much closer in the 20th minute. Jonny Hayes, making his first starting appearance for the club, found Sviatchenko with a free-kick from the left and his close range header was cleared off the line by Nicklas Bendtner.
That proved to be Sviatchenko’s last meaningful contribution. Making a challenge on Andreas Konradsen five minutes later, he sustained the knock to his right leg which left him unable to continue.
Celtic remained determined to stay on the front foot as much as possible and only a superb save by Andre Hansen prevented them taking the lead in the 27th minute. Tierney surged impressively down the left again, his low cross finding Forrest whose close range shot was diverted over the crossbar by the Rosenborg ‘keeper.
Hansen and Gordon were both called into action in the closing stages of the first half with a long range effort from Celtic captain Scott Brown and a header from Bendtner each easily dealt with.
Rosenborg began the second half with far greater intensity, moving the ball quicker and looking to press Celtic much higher up the pitch. The visitors appeared slightly taken aback and were relieved to see Yann-Erik de Lanlay, the man who missed a sitter for the Norwegian champions in Glasgow, drag a right foot shot narrowly wide after latching onto Bendtner’s lay-off.
Celtic were now finding it more difficult to find an outlet up front and with 57 minutes on the clock, Rodgers decided it was time for Griffiths to make his entrance. The increasingly peripheral Hayes was the man to make way. Griffiths wasted little time making his presence felt, whipping in a dangerous cross which Rosenborg scrambled clear before Scott Sinclair could make a connection.
The home side came close again when Jensen flashed a shot just wide of Gordon’s left hand post and there was a clear sense they were taking the initiative - until Forrest’s stunning goal completely altered the picture and put Celtic firmly in control of the situation.
Sinclair, having far from his best night in a Celtic shirt, came to life when he burst through the middle to pick out Forrest on the right of the penalty area. The winger, now back in his natural position, made a heavy first touch but regained control of the ball before smashing it high beyond Hansen via the underside of the crossbar.
Rosenborg were visibly deflated, now requiring two goals to salvage the tie. It was a task which was clearly beyond them and all of the conviction drained from their play. Celtic should have added gloss to the scoreline in the closing minutes, Forrest missing a simple chance to add to his tally, but he had already converted the one chance which was all the visitors needed.
ROSENBORG: Hansen, Hedenstad, Bjordal, Skjelvik, Meling; Jensen, Konradsen, Midtsjo; Jevtovic (Helland 73), Bendtner, De Lanlay (Vilhjalmsson 73). Subs not used: Ostbo, Rasmussen, Rashani, Gersbach, Lundemo.
CELTIC: Gordon, Lustig, Simunovic, Sviatchenko (Bitton 25), Tierney; Brown, Armstrong (Rogic 70), McGregor; Hayes (Griffiths 57), Forrest, Sinclair. Subs not used: De Vries, Gamboa, Ntcham, Kouassi.