CINCINNATI - Connor Gaardner scored off a rebound 1:28 into the second overtime Saturday night, sending North Dakota to a 2-1 victory over Ferris State and its 20th trip to the Frozen Four.
The seven-time national champions got an at-large berth and the fourth seed in the Midwest Regional when rival Wisconsin knocked off Ohio State for the Big Ten title. North Dakota (25-13-3) then knocked off top-seeded Wisconsin in the NCAA tournament semifinals.
Sophomore goalie Zane Gothbert had a career-high 44 saves, and Gaardner scored soon into the second overtime for North Dakota's first trip to the Frozen Four since 2011.
Ferris State (29-11-3) had several chances at the end of the third period and overtime, getting off nearly twice as many shots on goal.
Ferris State opened the scoring in the second period on Cory Kane's goal, and North Dakota tied it in the period on Stephane Pattyn's power-play score.
UNION 3, PROVIDENCE 1
BRIDGEPORT, Conn. (AP) ? Max Novak had a goal and an assist and top-seeded Union beat Providence to advance to the Frozen Four for the second time in three years.
Mat Bodie and Matt Hatch also scored for Union (30-6-4). The Dutchmen, who lost in the 2012 national semifinals to Ferris State, are ranked No. 1 in the nation for the first time in program history.
Nick Saracino scored with a little more than 5 minutes left in the third-period for Providence (22-11-6).
BOSTON COLLEGE 6, DENVER 2
WORCESTER, Mass. (AP) ? Johnny Gaudreau had his first hat trick for Boston College and added three assists, leading the top-seeded Eagles to past Denver.
Boston College (27-7-4) will face UMass-Lowell on Sunday for a spot in the Frozen Four.
Kevin Hayes had two goals and two assists, and Bill Arnold added a goal and two assists.
Denver finished 20-16-6.
UMASS-LOWELL 2, MINNESOTA STATE-MANKATO 1
WORCESTER, Mass. (AP) ??? Connor Hellebuyck made 35 saves and Joe Pendenza scored a short-handed goal in the first period in UMass-Lowell's victory over Minnesota State-Mankato.
UMass-Lowell (26-10-4), which reached the Frozen Four last season, ended Minnesota State's 13-game unbeaten streak (12-0-1) and kept the Mavericks (26-14-1) from earning their first NCAA Division I tournament win.
Hellebuyck came within 10.8 seconds of his seventh shutout of the season. After defenceman Zack Kamrass scored an empty-net goal to make it 2-0 with 40.9 seconds left, Zach Stepan scored on a power play.
MINNESOTA 7, ROBERT MORRIS 3
ST. PAUL, Minn. (AP) ??? Nate Condon scored twice and Adam Wilcox made 22 saves to help top-seeded Minnesota beat Robert Morris.
The Big Ten regular-season champion Gophers (26-6-6) will face St. Cloud State on Sunday for a spot in the Frozen Four.
Kyle Rau, Mike Reilly, Hudson Fasching, Michael Brodzinski and Justin Kloos also scored for Minnesota. The Gophers took a 3-0 lead in the first period and outshot the Colonials 50-25.
Cody Wydo, Zac Lynch and David Friedmann scored for Robert Morris (19-18-5).
ST. CLOUD STATE 4, NOTRE DAME 3, OT
ST. PAUL, Minn. (AP) ??? Nic Dowd scored with 2:39 left in overtime to lift St. Cloud State past Notre Dame.
Dowd, a Hobey Baker Award finalist who leads the Huskies with 22 goals, fired a wrist shot from the left circle that beat Steven Summerhays high.
Ryan Papa, Brooks Bertsch and Jonny Brodzinski also scored, and Ryan Faragher made 39 saves for the third-seed Huskies (22-10-5). Bryan Rust, Kevin Lind and Thomas DiPauli scored for Notre Dame (23-15-2).