Dundalk will head to Trondheim next week with their Champions League second qualifying round tie evenly poised after a 1-1 draw with Rosenborg at Oriel Park.
David McMillan's eighth goal in European football - which leaves him just three short of Glen Crowe's record Irish haul of 11 - gave the Lilywhites the perfect start after 18 minutes.
However, Stephen Kenny's side were pegged back when towering centre-back Tore Reginisussen took advantage of some shoddy defending in first-half stoppage time to bag a priceless away goal for the visitors.
Kenny's team selection threw up little in the way of surprises. Robbie Benson and Chris Shields occupied the midfield area with Stephen O'Donnell on the bench. John Mountney got the nod over Jamie McGrath on the right flank. New boy Dylan Connolly was also named amongst the substitutes.
Rosenborg named an unchanged line-up from the team that beat Sandefjord in the Norwegian league on Saturday with former Arsenal and Juventus striker Niclas Bendtner leading the attack.
Their line-up contained 11 full internationals but it was Dundalk who started on the front foot and they almost broke through after just 52 seconds.
A good move on the left ended with Dane Massey's lay-off falling kindly into Robbie Benson's path but the midfielder diverted the ball wide.
The visitors looked happy to sit back and allow Dundalk to dictate possession and they were happy to oblige.
Another opening arrived in the seventh minute, David McMillan teeing up Michael Duffy but the winger's effort was brilliantly saved by Anders Hansen, who initially looked he was going the wrong way.
The pressure eventually told 11 minutes later. Duffy, who along with fellow Derryman Patrick McEleney looked very inventive in the opening period, was involved.
The former Celtic winger cut in from the left to let fly with a right-foot curler and McMillan cut across its path, glancing the ball past the helpless Hansen to send Oriel Park wild.
Rosenborg offered little up to that point but they showed their teeth two minutes later when Bendtner was denied by a smart Gary Rogers save.
A couple of corners followed, pinning Dundalk back momentarily, but they broke rapidly with Mountney leaving Jorgen Skjelvik in his wake on the right. His cross found the incoming Duffy but he just couldn't adjust his feet to trouble the goal.
With Bendtner causing his Danish compatriot Niclas Vemmelund some bother, Rosenborg started to find some joy and Rogers had to make another fine stop on the half hour mark, blocking Pal Andre Holland's strike after the winger did brilliantly to create the opening.
A break in play allowed the Norwegians a chance to regroup in front of their dugout but they were forced into a change in the 42nd minute when Helland limped off to be replaced by Serbian Milan Jevtovic.
It looked like Dundalk would take a deserved lead into the dressing rooms at the break but they were undone by yet another sloppy goal in Europe.
Right-back Eggen Hedenstad's delivery, from a contentious free-kick, dropped dangerously in the Lilywhites six-yard box and the unmarked Reginiussen nipped in front of Brian Gartland to prod the ball home from close range.
The opening stages of the second half proved to be a lot more open and Rogers had to make another fine stop to smother Mike Jensen's drive after the Rosenborg captain was picked out by a cute Jevtovic pass on the inside right.
Vemmelund also departed with an injury, with Paddy Barrett, who played in all six of Dundalk's Champions League games last season, coming on in his place.
Kenny threw Dylan Connolly into the fray with 20 minutes to go and he almost made a stunning impact, darting towards a Mountney cross only to see the ball evade him at the far post.
Dundalk pushed for a second and McEleney got caught between two stools as he broke towards the Rosenborg penalty area with McMillan screaming to be played in.
Gartland and Kilduff then headed off target in the latter stages as Rosenborg held the League of Ireland champions at bay and they almost snatched the victory themselves in stoppage time but Dane Massey came across to snuff out a dangerous counter attack.
Dundalk: Gary Rogers; Sean Gannon, Brian Gartland, Niclas Vemmelund (Paddy Barrett 64), Dane Massey; Chris Shields, Robbie Benson; John Mountney, Patrick McEleney, Michael Duffy (Dylan Connolly 72); David McMillan (Ciaran Kilduff 81).
Rosenborg: Andre Hansen; Vegar Eggen Hedenstad, Tore Reginiussen, Johan Bjordal, Jorgen Skjelvik; Mike Jensen, Anders Konradsen, Matthias Vilhjalmsson; Pal Andre Helland (Milan Jevtovic 43), Niclas Bendtner, Fredrik Midtsjo (Yann De Lanlay 81).
Referee: Radu Petrescu (Romania).