Ruzicka extended the lead to 3-1 at 4:31 of the second period when he knocked in his own rebound from in front.
"Great feeling for me and for my family watching from back home (in Slovakia), but I'm pretty upset that we lost this one," Ruzicka said.
Karlsson cut it to 3-2 at 10:08, beating Vladar five-hole on a breakaway after exiting the penalty box and receiving a pass from Couture, who then tied it 3-3 at 14:27 when he redirected Karlsson's point shot on the power play.
"Feels good right now after a tough end to our road trip there," Couture said. "Both games that we lost on the road trip, we had a sour taste left in our mouths. So down 3-1, it could have gone either way there, and I'm glad we stuck with it.
"[Karlsson's goal] gave us some energy. Brought some energy back into the building."