Alex Edler scored the winning goal 1:21 into the extra session. He fired in a quick shot while given loads of time with the puck by the side of the net and motioning to pass.
Demko earned a win in his NHL debut with the Canucks after being called up from Utica of the American Hockey League on an emergency basis. He was summoned to fill in for Anders Nilsson, who has been ill.
The Canucks led 4-1 with just under six minutes left in the third period, but the Blue Jackets rallied with three goals in just over two minutes.
Demko led the Canucks to their fourth straight victory. The Blue Jackets suffered only their second loss in 14 contests.
Jussi Jokinen, 34, led the Canucks with a goal and two assists. The former Blue Jacket stole the show from high-scoring winger Thomas Vanek, who was held pointless in his first game against the Canucks since being dealt to Columbus from Vancouver at the trade deadline in February.
Jokinen came to Vancouver as part of the Vanek trade. Although he was considered a throw-in, Jokinen now has seven points in 11 games as a Canuck.
Darren Archibald, Nikolay Goldobin and Bo Horvat also scored for Vancouver.
Seth Jones had a goal and three assists for the Blue Jackets, while Pierre-Luc Dubois, Zach Werenski and Cam Atkinson also scored. Artemi Panarin earned assists on all four Columbus goals.
Blue Jackets goaltender Joonas Korpisalo blocked 24 of 29 shots. Columbus scored on 2 of 3 power plays, while the Canucks were blanked on one.
Jones opened the scoring on a power play 13:55 into the game as he wired home a slapshot from the blue line.
Archibald drew the Canucks even at 11:53 of the second period as he skated with the puck down the left wing, retrieved his blocked pass attempt, kept going and put a shot off Columbus defenseman David Savard's skate and over Korpisalo's catching glove.
Goldobin put the Canucks ahead 2-1 at 13:37 of the middle frame as he passed to Jokinen, set himself up to shoot and then fired Jokinen's quick return pass behind Korpisalo.
Jokinen gave the Canucks a 3-1 lead at 5:14 of the third period as he put in Jake Virtanen's pass from behind the net. Horvat padded Vancouver's lead, on a pass from Jokinen, at 14:03 of the final frame.
Dubois brought Columbus within two goals on a power play at 16:02 as he put in a pass from Panarin. Columbus coach John Tortorella pulled Korpisalo in favor of an extra attacker with more than two minutes left, and the move paid off as Werenski put in a cross-ice feed from Panarin with 1:37 left in regulation time.
Only 16 seconds later, Atkinson deflected in a Jones shot to force overtime.
--Field Level Media
Columbus | Vancouver | |
Seth Jones 4 | Points | Jussi Jokinen 3 |
Seth Jones 1 | Goals | Jussi Jokinen 1 |
Artemi Panarin 4 | Assists | Jussi Jokinen 2 |
Seth Jones 1 | Power Play Goals | N/A |
N/A | Short Handed Goals | N/A |
Joonas Korpisalo .828 | Save Percentage | Thatcher Demko .867 |
Joonas Korpisalo 24 | Saves | Thatcher Demko 26 |
Team | Shots | Goals | Power Play | Penalty Kill | Penalty Mins | Face Offs Won |
Columbus | 30 | 4 | 2-3 | 1-1 | 2 | 39 |
Vancouver | 29 | 5 | 0-1 | 1-3 | 6 | 28 |