Larsson had a very nice solo effort to earn his second goal of the game.
The Swedish defender crossed three-quarters of the ice before going for a shot that bifurcated on the right skate of defender Josh Manson, thus foiling the vigilance of goalkeeper John Gibson.
Mark Letestu also hit the mark twice for visitors. Leon Draisaitl put the finishing touches in a desert net, with 1:05 on the dial.
Cam Talbot stopped 33 shots, being thwarted by Ryan Getzlaf, Patrick Eaves and Jakob Silfverberg.
Gibson made 27 saves for the Ducks, who will also host the second game on Friday.
Getzlaf first scored on power play, 37 seconds after the faceoff that kicked off the second period. Anton Slepyshev had hung up late at the first twenty.
Letestu replied with two goals with the advantage of a man: at 6:22 in the second period and at 6:23 at the third engagement, taking advantage of rebounds.
At 8:03, Larsson reaped what appeared to be an insurance goal, with a shot from the enclave.
Eaves narrowed the gap to 9:22 on the rebound of a shot from Brandon Montour.
Only 1:25 later, Silfverberg created the deadlock 3-3 by hitting the record uncontrolled by Talbot, on a shot from Andrew Cogliano. That was before Larsson took charge.