And about 3 minutes into the third period, Joyce stuck in a rebound of a shot by Brent Bobyck, who took a pass from Hrkac.
UND goalie Ed Belfour held St. Lawrence in check after surrendering a goal to Dave Saunders at 1:17 into the first period. Rick Mulligan and Mike Hurlbut assisted on the St. Lawrence goal.
The game featured fine goaltending by both Belfour and Yearwood. Each recorded 38 saves.
Beflour stopped all five St. Lawrence power plays, while Yearwood provided few opportunities for North Dakota to take advantage of rebounds.
"Great goaltending on both ends of the rink," UND Coach Gino Gasparini said. "I thought we could bust open the game in the third period but Yearwood made several saves."
North Dakota, the No. 1-ranked team in the country and 37-8 on the year, and St. Lawrence (24-10) will play their final game Saturday night to determine who will reach the Final Four in Detroit next week.
Michigan St. 6, Maine 2
Right wing Kevin Miller had a goal and assist last night to lead Michigan State to a 6-2 victory over Maine in NCAA hockey playoff action.
Maine led 1-0 after the first period before the Spartans scored three times in the second period on goals by defensemen Don McSween, Tom Tilley and Bruce Rendall.
Maine right wing Guy Perron scored his second goal of the contest, a power-play tally 2:38 into the third period, to bring the Black Bears to within 3-2. But Michigan State scored three times in the final 12:29, including goals by Mitch Messier, Brian McReynolds and Miller.
Michigan State goaltender Norm Foster made 33 saves, while Maine's Al Loring stopped 26 shots.
The two-game, total-goal series resumes here Saturday night. The winner advances to the NCAA semifinals next Thursday at Detroit's Joe Louis Arena.
The victory lifted Michigan State's record to 31-9-2, while Maine fell to 24-15-2.
Crimson, 7-1 at Bright Center Bowling Green 0-1-0--1 Harvard 3-3-1--7
First Period--1, H, Steve Armstrong 11 (Josh Caplan, Chris Biotti) 1:27;2, H, Lane MacDonald 36 (Randy Taylor, Allen Bourbeau) 4:51; 3, H, Don Sweeney 7 (Armstrong, Caplan) 16:41. Penalties--BG, Kevin Dahl (roughing) 3:54; H, Andy Janfaza (slashing) 3:54; BG, Iain Duncan (interference) 4:21; BG Thad Rusiecki (holding) 14:54.
Second Period--4, H, C.J. Young 15 (unassisted) 3:09; 5, H, Young 16 (Tim Barakett, Sweeney) 8:00; 6, H, Bourbeau 21 (MacDonald, Barakett) 11:37; 7, BG, Duncan 28 (Nelson Emerson, Don Barber) 18:32. Penalties--H, Barakett (tripping) 2:01; BG, Dahl (tripping) 8:00; BG, Scott Paluch (elbowing) 10:43; H, Nick Carone (highsticking) 16:41.
Third Period--8, H, Barakett 24 (Taylor, Bourbeau) 11:07. Penalties--BG, Barber (roughing) 8:03; Bg, Rob Urban (roughing) 8:03; H, MacDonald (roughing) 8:03; H, Caplan (roughing) 8:03; BG, Duncan (checking after the whistle) 10:00; Marc Potvin (charging) 17:51.
Saves--BG, Gary Kruzich 12-9-13--34; H, Dickie McEvoy 7-11-11--29.
A:3350