Blackhawks 3, Blues 2 (OT): Captain Jonathan Toews scored on a breakaway 7:36 into overtime as visiting Chicago won its third straight contest to take a 3-2 lead in its Western Conference first-round series with St. Louis.The Central Division rivals ventured into overtime for the fourth time in five games before a poor line change did in the Blues. Toews came off the bench and collected a feed from defenseman Duncan Keith at center ice before skating in and backhanding a shot past the outstretched left pad of Ryan Miller (27 saves).Marian Hossa and Ben Smith also scored while Corey Crawford finished with 27 saves for the Blackhawks, who can wrap up the series at home in Game 6 on Sunday afternoon. Chicago won both contests at the United Center in the series - a 2-0 victory in Game 3 and a 4-3 overtime triumph in Game 4. T.J. Oshie and defenseman Alex Pietrangelo tallied for the Blues, who saw captain David Backes return from a two-game absence due to an upper-body injury.Hossa poked home his own rebound with 3:49 remaining in the first period as Chicago opened the scoring. Oshie beat Crawford with a backhand shot while falling to the ice midway into the second before Smith regained the lead for the Blackhawks by shoveling a backhander under the crossbar with 2:50 left in the session. Pietrangelo forged a tie by converting a 2-on-1 rush 1:42 into the third.GAME NOTEBOOK: Backes was injured on an illegal hit by Chicago D Brent Seabrook, who served the final contest of his three-game suspension. ... Both teams failed to score on two power-play opportunities. St. Louis is 2-for-23 in the series while Chicago is 2-for-18 ... Prior to his third career playoff goal, Oshie had been held without a point since recording a hat trick versus Minnesota on March 27.