Seguin got a shot past Karri Ramo in the first round of the shootout, and Stars goalie Kari Lehtonen was perfect against Joe Colborne, Johnny Gaudreau and Sean Monahan to get the victory.
Jamie Benn also scored for Dallas, which pulled six points behind Winnipeg for the second wild-card spot in the Western Conference.
Dereky Engelland got his first two goals of the season, and Gaudreau also scored in regulation for Calgary. The Flames remained third in the Pacific Division, one point up on Los Angeles — which is outside of a playoff spot.
FLYERS 4, BLACKHAWKS 1
PHILADELPHIA (AP) — Claude Giroux, Wayne Simmonds, Ryan White and Michael Raffl scored goals to lead Philadelphia past Chicago.
Giroux had his 22nd goal for his first even-strength score at home this season. Steve Mason was stout again for the Flyers, finishing with 34 saves.
Andrew Shaw scored for the Blackhawks.
Flyers fans gave Chicago defenceman Kimmo Timonen a standing ovation during a video tribute for the returning defenceman who helped lead Philadelphia to the 2010 Stanley Cup final.
Timonen returned to Philadelphia for the first time since he was traded to Chicago in February for two draft picks.
OILERS 4, AVALANCHE 3
EDMONTON, Alberta (AP) — Derek Roy scored the tiebreaking goal midway through the third period and Edmonton recovered after giving up a three-goal lead.
Martin Marincin, Jordan Eberle and Taylor Hall all scored in the first 9:36 of the game for the Oilers, who have won two of their last three games. Ben Scrivens stopped 31 shots.
Jarome Iginla and Alex Tanguay scored in the second period, and Ryan O'Reilly tied it early in the third for the Avalanche, who have lost three in a row and are 10 points out of playoff spot with just nine games remaining.
Semyon Varlamov allowed three goals on the first seven shots he faced before getting pulled in favour of Reto Berra, who finished with 26 saves.