Jaden Schwartz and Sammy Blais scored third-period goals 33 seconds apart on Sunday to help spark the St Louis Blues over host Dallas 4-1 and equalise their National Hockey League (NHL) playoff series.

The victory leveled the best-of-seven Western Conference second-round series at 3-3, setting up Tuesday’s game seven decider in St Louis.

“It was a do-or-die game for us,” said Blues standout Colton Parayko. “I was proud of how we played in the third period. Now it’s going to be even bigger in game seven.”

The winner will face either the Colorado Avalanche or San Jose Sharks in the Western Conference final.

St. Louis has never won the Stanley Cup since the team began play in 1967 and the Blues haven’t reached the NHL final since 1970.

The Stars won their only Stanley Cup in 1999 and they have not reached the conference finals since 2008.

Blues defenceman Alex Pietrangelo opened the scoring 63 seconds into the game, St. Louis producing the contest’s first eight shots on goal.

Tyler Seguin answered with an equaliser for Dallas, the Canadian centre connecting on a power play goal with 8:25 remaining in the first period.

David Perron’s tip-in goal put the Blues back on top with 4:36 remaining in the second period.

A key moment came in the third when Parayko’s slapshot struck Dallas goaltender Ben Bishop in the left collarbone area, the puck popping up and away as Bishop fell to the ice in pain.

“Just saw a lane so I tried to fire one,” Parayko said. “Tried to score and I clipped him a little high I suppose.”

Alex Steen of St. Louis got the puck and flipped it to Schwartz, who tipped the puck into the vacant net 7:37 into the third period for his eighth goal of the playoffs.

NHL play is not stopped until the team with the injured player gains possession of the puck. Referees make the decision whether or not to stop play earlier based on their assessment of the severity of the injury.

Barely half a minute later, Blais skated in on a breakaway and fired the puck over Bishop’s right shoulder into net for his first playoff goal and to give the Blues a 4-1 lead.

Dallas removed Bishop, sending him to the locker room for treatment while reserve Anton Khudobin finished the game.

Jordan Binnington made 22 saves for the Blues.