FIRST, IT was Jonathan Toews on a power play, and then Patrick Sharp got loose on a breakaway. Andrew Shaw tipped one home, and it was all over.

One dazzling stretch for the Chicago Blackhawks put an end to their tight, first-round series against the St. Louis Blues.

Duncan Keith had a goal and three assists, and the Blackhawks used a four-goal third period to finish off the Blues with a 5-1 victory in Game 6 yesterday in Chicago.

"It feels good to contribute in a big game," Keith said, "and I think just the main thing for me is just being able to move on and get a couple days to relax and just regroup and focus on the next round."

Chicago won four in a row after a slow start in St. Louis, where they lost the first two games of the series. The defending Stanley Cup champions will play the winner of the Minnesota-Colorado series in the Western Conference semifinals. The Avalanche leads the Wild, 3-2, heading into Game 6 in Minnesota tonnight.

Toews, Sharp and Shaw scored in the first 7 1/2 minutes of the third and Keith closed out the scoring as the Blackhawks improved to 14-2 in home playoff games over the past two seasons.

Bryan Bickell scored in the first and Corey Crawford made 35 saves, keeping Chicago in a tie game when St. Louis controlled the second period.

"They were dominating the first 40 minutes here and we came back with maybe the best period of the year," Blackhawks coach Joel Quenneville said.

St. Louis went 0-for-6 in 10 minutes of power-play time over the first two periods, wasting a chance to take the lead. The Blues went 2-for-29 with the man advantage for the series.

The Blackhawks also struggled on the power play, but they scored when it mattered most.

With Jay Bouwmeester in the box for tripping, Keith made a nice stop to keep the puck in the St. Louis zone, and then sent a pass over to Toews. The captain beat Miller over his right shoulder for a 2-1 lead just 44 seconds into the third.

It was Toews' third game-winning goal of the series. He also scored on a breakaway in overtime of Friday night's 3-2 win.

Toews' 23rd career postseason goal seemed to take the air out of the Blues, and it got even worse for St. Louis. Sharp got loose for a breakaway, shook off a stick to the face by defenseman Kevin Shattenkirk and slid a shot past Miller.

"The third goal was really a backbreaker for us," Blues coach Ken Hitchcock said. "That was really the one that hurt. We had been chasing them all series and able to catch up in games, but I thought the third goal really took the wind out of our sails."

It was an eerily similar playoff exit for St. Louis to a year ago, when the Blues also were eliminated by the defending Stanley Cup champions in six games in the first round. In that 2013 playoff series, St. Louis won the first two games at home against Los Angeles, and then lost four in a row.

In another game

* At Dallas, Nick Bonino scored 2:47 into overtime, after getting one of Anaheim's two goals late in regulation, and the Ducks beat the Stars, 5-4, in Game 6 to clinch the first-round series.

The Ducks scored twice in the final 2:10 of regulation to force overtime for the first time in the series.