The hosts were clinical early on as they opened the scoring with the first real chance of the game. It needed VAR to confirm that Dion Drena Beljo had stayed onside when he touched home Matteo Perez Vinlof’s drilled ball across the box after just six minutes.
Four minutes later, no such scrutiny was required when Beljo pounced on Henrik Falchener’s loose back pass and turned provider, slipping in Mateo Lisica to double Dinamo’s lead after just 10 minutes.
It was shaping up to be a long night in the Croatian capital for the Norwegian champions, and it almost got worse on 23 minutes, but Miha Zajc came a post’s width from making it three.
However, to their credit, Viking struck back just before the half-hour mark somewhat against the run of play. Tobias Moi’s clever pass slipped in Peter Christiansen, who finished clinically into the roof of the net.
That gave De Morkebla a jolt of confidence, and after gaining a foothold in the game, an unlikely leveller six minutes before the break followed.
It was Moi again with the assist, picking out captain Zlatko Tripic on the left side of the penalty area, allowing the Croatian-born midfielder to open up his body to finish neatly off the inside of the far post.
Kicking off the second period all square after an enthralling first half, it was Mario Kovacevic’s men who had the first chance when Luka Stojkovic headed wide from Sergi Dominguez’s cross.
Purgeri were dominating possession and territory but struggling to test Arild Ostbo until he was forced into action in the 73rd minute, tipping Mislav Orsic’s snapshot smartly around the post.
Viking had been on the back foot for much of the second half, but they came close to stealing a late advantage when Gianni Stensness came inches away from connecting with Christiansen’s cutback.
It was Dinamo who threatened late with a pair of opportunities but, ultimately, this tie will go back to Stavanger on level terms, with the Croatian side still unbeaten this season.
Flashscore Man of the Match: Dion Drena Beljo (Dinamo Zagreb)