The Fighting Saints scored just over a minute into the first period, and less than a minute into the second, en route to a 3-2 victory at the Mystique Community Ice Center in Dubuque.
The Lumberjacks are now 16-18-4 on the season, good for 36 points and last place in the USHL’s Eastern Conference.
Willie Knierim scored the first period goal for Dubuque, then the Lumberjacks answered with a power play goal by Collin Adams to tie the score 1-1 at the first intermission.
Nathan Sucese scored the early goal in the second period for Dubuque, then added another goal in the third period, to put the Fighting Saints up 3-1.
Muskegon cut the deficit to 3-2 with 10:19 remaining when Tyler Irvine scored his fourth goal of the season. But the Lumberjacks could get no closer.
Muskegon was outshot 36-24. Lumberjack goalie Devin Cooley stopped 31 of 34 shots.
The two teams will have a rematch in Dubuque on Saturday night.