Jonathan Toews scored on a low shot from the left circle at 3:19 of overtime to give Chicago a 4-3 victory over the St. Louis Blues on Wednesday night and move the Blackhawks within two points of a clinching a playoff spot in the Western Conference.

Toews beat Ty Conklin on the short side after taking a long lead pass from Duncan Keith and racing in with Blues defenseman Carlo Colaiacovo in close pursuit.

Chicago's Marian Hossa, Tomas Kopecky and Nick Leddy scored in the second period to help the defending Stanley Cup champion Blackhawks erase a two-goal deficit.

St. Louis' Chris Stewart scored midway through the third to set up overtime. T.J. Oshie had a goal and an assist, and David Backes also scored for the Blues, who are out of the playoffs for the second straight season.

Backes' goal was his 31st, matching his career high set in 2008-09.

The Blackhawks, 3-3-1 in their last seven, have two games remaining with Detroit. Patrick Sharp, Chicago's leading goal scorer with 34, returned after missing seven games because of an injured left knee.

He assisted on Hossa's goal at 7:52 of the second that cut the Blues' lead to 2-1 — and got the Blackhawks' offense rolling. The goal withstood a 6-minute video review.

Sharp flipped a centering pass into the crease that deflected into the net off Hossa's left skate. It also wasn't clear if the puck completely crossed the goal line before Conklin swept it out.

Chicago rookie Corey Crawford made 21 saves in his 25th straight start.

Conklin stopped 35 shots in his 200th NHL game.

Backes was credited with the only goal of the first period just 17 seconds in following a Chicago turnover. Andy McDonald picked off Hossa's outlet pass from the right boards, then slipped the puck to Oshie. Oshie's 30-foot shot from the slot deflected off Backes and then off the top of the left post before landing behind Crawford.

The Blackhawks failed to convert a 5-on-3 power play that lasted 1:44 midway through the first, and managed only three shots during the advantage.

Oshie's power-play goal 1:06 into the second made it 2-0. His high shot from the top of the right circle handcuffed Crawford and slipped past on the stick side.

Hossa's goal at 7:52 cut it to 2-1. Following the video review, referee Dan O'Halloran announced the puck had crossed the goal line.

And after the ruling, Chicago began playing with more cohesion and confidence. Kopecky tied it at 2 with 6:37 left in the second by swatting in a bouncing puck from the left edge of the crease.

Leddy put Chicago ahead 3-2 with 1:50 remaining in the period on a screened drive from the left point. Stewart scored managed to flip in a shot from the slot and tie it 3-all at 9:44 of the third, despite being tied up by Leddy and Keith.

In overtime, Conklin made point-blank saves on Toews and Viktor Stalberg before Toews' goal. Moments before Toews' winner, a shot by Oshie hit Crawford in the mask.

NOTES: The Blackhawks recalled RW Ben Smith from Rockford of the AHL. He appeared in three games earlier this season. ... St. Louis RW Cam Janssen was a healthy scratch.