Swedish clubs Frolunda, Brynas and Lulea all recorded wins in yesterday's first legs - two of which were at the expense of Lukko's domestic rivals, Ilves and KalPa, respectively - meaning as things stand only Swedish Hockey League and Liiga sides will reach the last four.
Lukko ensured they did what was required of them on home ice, breaking the deadlock with a minute of the first period to play, when Anton Olsson was perfectly placed to tuck away a rebound.
Zug made life tougher for themselves six minutes into period two, when they gave up possession in their own zone to Ponthus Westerholm, who set up Aarne Intonen to make it 2-0 with a one-timer.
Though Mike Kunzle halved the deficit in the first minute of the third, Lukko restored their two-goal lead just over two minutes later, as Westerholm turned from provider to scorer, with his brother Pathrik grabbing an assist.
That was enough for the Rauma side to claim victory, and they will travel to Switzerland for the return leg on 16th December with a 3-1 advantage.
Review all this week's CHL Quarter-final ties on Flashscore.
