A brace from Harry Winks, including one from the penalty spot, saw us recover from two early goals conceded from set pieces, before Nathan Oduwa and Will Miller fired us into a 4-2 lead in the second half.
A fine piece of trickery and a further set piece situation saw the visitors draw level in the closing stages, with Rosenborg forward Andreas Helmersen completing his hat-trick.
Four minutes were on the clock when the visitors took the lead at our Training Centre, Aslak Fonnwitry curling in a 22-yard free-kick after Josh Onomah was adjudged to have tripped Helmersen.
Six minutes later it was 2-0 as John Hou Saether’s corner was met by Helmersen, whose header crashed in off the underside of the bar.
We pressed forward in search of a way back into the game, forcing five corner kicks in a short space of time around the quarter-of-an-hour mark. From one of those, Dominic Ball headed Winks’ cross back into the danger zone, with Connor Ogilvie’s volley being charged down at the expense of a further corner.
Winks took it again and this time it was Oduwa who met it, but his low effort was blocked on the line and Rosenborg were able to scramble the ball away.
Miller ran onto Ogilvie’s cross and produced a save from the visiting goalkeeper on 27 minutes – going closer still two minutes later when he swept Alex McQueen’s ball in against the post.
After much probing we were presented with a chance to pull a goal back when Kenny McEvoy burst into the box and won a penalty, Winks sending the keeper the wrong way from 12 yards.
The same player restored parity on 37 minutes when he seized a loose ball after a slip in Rosenborg’s midfield and drilled low into the bottom corner of the net from 25 yards out.
Four minutes into the second half Josh Onomah fed Oduwa and his effort crept between the keeper’s legs to make it 3-2, before Oduwa turned provider for our fourth goal on 53 minutes – the attacker storming down the left and pulling the ball back for Miller to force it home from 10 yards.
It was then Rosenborg’s turn to mount a comeback. Hou Saether cleverly slipped the ball in to Helmersen with a deft flick using the inside of his boot and the visiting forward doubled his personal tally for the afternoon on 65 minutes.
Helmersen completed his treble 10 minutes later when he curled a free-kick around the defensive wall and inside the near post while Per Magnus Steiring tried his luck shortly afterwards, only for his rising drive to be kept out by a fine Luke McGee save.
Pictured above: Kenny McEvoy surges forward