A flat performance by Colorado College dropped the Tigers to their third-straight last-place league finish.
No. 8 Western Michigan never trailed and used a three-goal second period to put away CC 5-1 in the regular-season home finale Saturday at The Broadmoor World Arena.
It was a lackluster outing for the Tigers, who did not play with nearly the same energy displayed in Friday's 3-3 tie.
"There was no energy tonight," CC hockey coach Mike Haviland said. "It was almost like we threw everything we had last night and we had nothing tonight."
With the loss, the Tigers (7-21-4, 3-15-4-1 league) finished the regular season with a 1-13-2 home record.
Now assured of the eighth seed, Colorado College will travel to the National Collegiate Hockey Conference regular-season champion - either top-ranked Denver or No. 2 Minnesota-Duluth - to open the playoffs on March 10.
The hosts entered the game with a slim chance at seventh but WMU crushed that hope in the second en route to the Broncos' first-ever win in Colorado Springs (1-4-3).
CC had cut into a 3-0 Western Michigan lead thanks to a strong individual play by senior Luc Gerdes. He cut to the front of the Broncos net and drew two WMU defenders before making a pass to a wide-open Trevor Gooch for a power-play goal with 7:19 left.
It invigorated a quiet home crowd but Western Michigan went ahead by three about five minutes later on a power-play tally by Corey Schueneman, who scored seven seconds after his first shot attempt caromed off the crossbar. He made the second shot from the same spot count.
A defensive breakdown helped WMU record the game-winner when sophomore Matheson Iacopelli got behind the CC defenders and hauled in a long pass from defenseman Luke Bafia. He faked low and then lifted the puck over freshman goalie Alex Leclerc (20 saves) with 12:53 left in the second for a 2-0 lead.
"I thought maybe we would respond after (a slow first period) in the second and then we make a major mistake with a breakaway goal," Haviland said. "It never looked like we had our legs from the start."
CC goalie Derek Shatzer started the third and made four saves in the third.
"We needed a spark," Haviland said. "He's a senior. His parents were here and it was the right thing to do."
The victory clinched third place and home playoff ice for the Broncos (19-8-5, 12-8-2-1 league) for the first time in the NCHC's fourth season.