Keith scored at 16:12 of the third period, making it his second game-winner of the series. He found the back of the net for the game-winning goal in Chicago's double-overtime win in game 1. He also added 2 assists in Saturday's game-6 victory.
Jonathan Toews, Patrick Sharp, and Patrick Kane scored the 3 first period goals for the Blackhawks, while Corey Crawford had 13 saves after replacing Scott Darling. The rookie surrendered all 3 of Nashville's goals.
The Blackhawks will move on to face the Minnesota Wild, their division rival, in the second round. They eliminated the Wild last year in the playoffs. Minnesota took their series from the St. Louis Blues 4-2.
The Blackhawks are looking for their third Stanley Cup since 2010.
The Calgary Flames fell into a quick 3-0 hole on Saturday, but they came back in the most impressive way to knock out the Vancouver Canucks. The Flames outscored the Canucks 7-1 the rest of the way for a 7-4 game-6 win to take the series.
Matt Stajan broke a tie with 4:17 left in the game to help Calgary take the series 4-2. The Flames move on to face the top-seeded Anaheim Ducks, as they advance into the second round for the first time since 2004. They reached the Stanley Cup Finals that season and lost in seven games to the Tampa Bay Lightning.
Jiri Hudler and Michael Ferland each scored twice, and Sean Monahan and Johnny Gaudreau each added one of their own. Hudler tied the game at 4 with a power play goal at 6:14 of the third period.
Luca Sbisa, Brandon McMillan, Jannik Hansen, and Radim Vrbata all scored for the Canucks, who led 3-0 midway through the first. The Flames pulled goalie Jonas Hiller in the first after he gave up 3 goals on the first 4 shots. Karri Ramo stopped 17 of 19 shots in relief.
Ryan Miller made 28 saves in the Canucks final game of the 2015 season. The Flames lost 3 of 5 games against their second round opponent during the regular season.