Ryan Poehling had a goal and an assist, Cutter Gauthier and Mikael Granlund each scored, and Lukas Dostal made 29 saves for the Ducks (38-27-4), who have won two of their last three games.
Anaheim remains in first place in the Pacific Division, extending its lead over the second place Edmonton Oilers by three points despite having played one fewer game.
Dylan Guenther scored and Vitek Vanecek made 20 saves for the Mammoth (36-28-6), who have lost five of their last seven games (2-3-2).
Guenther opened the scoring at 1:48 of the first period, beating Dostal over the blocker from the left dot with a one-timer set up by Sean Durzi to give the Mammoth a 1-0 lead.
Poehling scored a short-handed goal at 13:37, digging the puck off of the left boards and beating Vanecek on the blocker side with a wrist shot on a breakaway to tie the game at 1-1.
Killorn scored at 9:09 of the second period, beating Vanecek off a pass from Beckett Sennecke to give the Ducks a 2-1 lead.
Gauthier scored an empty-net goal at 18:24 to make it 3-1. With the secondary assist on the goal, John Carlson recorded his first point as a Duck since being traded to Anaheim on March 6 by the Washington Capitals for a conditional first-round pick in the 2026 NHL Draft and a third-round pick in the 2027 NHL Draft.
Just 41 seconds later, Granlund scored another empty-net goal at 19:05 for the 4-1 final.
