ST. LOUIS — Boston University got second-period goals from Jack Hughes and Cole Eiserman, and Mikhail Yegorov made 32 saves to help the Terriers defeat Penn State, 3-1, Thursday night and advance to the national championship game for the first time since 2015.

The Terriers will face Western Michigan, which defeated defending national champion Denver, 3-2, in double overtime, as they search for their first title since 2009 on Saturday at 7:30 p.m.

After a scoreless first period, BU finally broke through when Hughes was able to poke in a rebound of Matt Copponi’s shot at 1:35 of the second period. Copponi fired a shot from the left circle that Arsenii Sergeev (31 saves) stopped, but he lost track of the puck, which was resting in the crease before Hughes came charging in to poke it into the net.

The lead grew to 2-0 when Cole Hutson and Eiserman broke in for a 2-on-1, with Hutson carrying the puck down the left side before sending it over to Eiserman for the one-timer and his team-leading 24th of the season. The two were sprung for the breakaway off a nice backhand pass from Devin Kaplan from behind the BU net.

After Penn State cut the lead in half early in the third, Jack Harvey sealed the win with an empty-netter.

Follow Andrew Mahoney @GlobeMahoney.