Chicago Blackhawks-St. Louis Blues: NHL playoff preview and who will win series

--Key Matchup: Blues penalty-kill vs. Blackhawks power play.

Chicago has struggled to possess the puck during 5-on-5 play, and that's not likely to change in the playoffs. If that continues, it will put a strain on the Blackhawks' defense, goaltending and especially their special teams. More specifically, it will put pressure on Chicago's power play to be as good as it was in the regular season.

Led by the high-scoring line of Artemi Panarin, Artem Anisimov and Patrick Kane, the Blackhawks' power play finished the regular season second in the NHL in efficiency (22.6 percent). The Blues finished third in penalty-killing (85.1 percent success rate) and should provide a strong challenge for Chicago's power-play units, led by red-hot goalie Brian Elliott.

--X Factor: Blackhawks goalie Corey Crawford.

Crawford allowed five goals in each of his final two starts during the regular season, and those appearances were separated by nearly a month because of an upper-body injury. Prior to the injury, Crawford was having a career-best season. The two-time Stanley Cup winner had great numbers and was in the discussion for the Vezina Trophy.

Crawford's play this season is a big reason the Blackhawks stayed among the NHL's top teams. Chicago didn't have the puck nearly as much as previous seasons, but the wins still piled up thanks to Crawford's play. During the Blackhawks' franchise-record 12-game win streak from Dec. 29-Jan. 19, Crawford made nine starts and went 9-0-0 with a 1.88 goals-against average and .946 save percentage. If he can regain top form quickly, it could swing the series heavily in Chicago's favor.

--Who Wins: Blues in six.

Chicago has won the Stanley Cup three times in the past six seasons for a reason. The Blackhawks have a core group of elite players and never seem to lose hunger for winning championships. Desire, however, only gets you so far.

Chicago's struggles in puck-possession stem from offseason roster depletion that was necessitated by the NHL's strict salary cap. Acquiring Andrew Ladd at the trade deadline filled a glaring hole at left wing on the top line, but the Blackhawks were unable to replace Johnny Oduya on the second defense pairing. Chicago's offense is created by its defense. When the defense struggles to clear its own zone, everything bogs down.

The Blues often get labeled as merely a big, physical team, but are much more skilled than some realize. St. Louis has the edge defensively, but also has high-end talent up front. In the end, it will be too much for the Blackhawks to handle.