AJ Greer also scored for the Flames, who received a scintillating 27-save performance from goaltender Dan Vladar.
William Karlsson tallied for the Golden Knights, the defending Stanley Cup champions who are sputtering on a 3-5-2 run and have scored only three goals in their past four games. Goalie Adin Hill stopped 32 shots.
Late in the extra session, Weegar grabbed the puck deep in his zone, weaved through the Golden Knights and ripped a shot from the right faceoff dot for his fifth goal of the season and the first overtime winner of his career.
Blue Jackets 5, Bruins 2
Yegor Chinakhov's goal and assist helped Columbus to a victory over visiting Boston, sending the Bruins to their longest skid in a year-and-a-half.
The Blue Jackets dominated with a 40-33 advantage in shots on goal, including 19-9 in the second period, as they won for the third time in four games and forced Boston to make its first in-game goaltender change of the season. Bruins coach Jim Montgomery replaced Jeremy Swayman with Linus Ullmark in the second period after Columbus' second goal.
Rookies Matthew Poitras and John Beecher each scored in the third period for Boston, which has lost three straight in regulation for the first time since April 2022.
Panthers 5, Senators 0
Sam Reinhart had two goals and Sergei Bobrovsky needed to make just 20 saves for his 40th career shutout as Florida rolled to a victory over host Ottawa.
Sam Bennett had a goal with an assist, Carter Verhaeghe and Eetu Luostarinen scored late and Aleksander Barkov assisted on each of the season-high three power-play goals for Florida, which avoided a third straight loss.
Joonas Korpisalo stopped 33 shots for the Senators, who have dropped two straight after winning three in a row.
Sabres 5, Rangers 1
Alex Tuch scored twice and Ukko-Pekka Luukkonen made 25 saves as visiting Buffalo rebounded from one of its worst showings of the season by beating New York.
Luukkonen helped the Sabres recover from a horrific defensive showing in a 7-2 loss to the New Jersey Devils on Saturday. He highlighted his third straight win by making a diving stick save on Jimmy Vesey's attempt into a vacated net to protect a two-goal lead early in the third period.
New York had gone 11-0-3 in the teams' past 14 meetings.
Avalanche 4, Lightning 1
Ryan Johansen scored two goals and Cale Makar had a goal and an assist as Colorado beat Tampa Bay in Denver.
Valeri Nichushkin also scored for the Avalanche, Alexandar Georgiev turned away 40 shots and Nathan MacKinnon had two assists to extend his home point streak to 10 games. Colorado has won four consecutive games and seven of its past eight.
Anthony Cirelli scored and Andrei Vasilevskiy had 20 saves in his second game of the season for the Lightning.
Sharks 2, Capitals 1
Luke Kunin scored the go-ahead goal on a power play at 12:48 of the third period and San Jose beat visiting Washington in a matchup of the two lowest-scoring teams in the NHL.
Fabian Zetterlund also scored for the Sharks, and Mackenzie Blackwood made 33 saves. The Sharks have won back-to-back games for the second time this season. After starting 0-10-1, San Jose is 5-5-1 in its past 11 games.
Evgeny Kuznetsov scored for the Capitals, who have lost two straight and were opening a five-game road trip. Darcy Kuemper stopped 21 shots.
