The Blues and Colorado Avalanche entered their matchup Thursday night as owners of the top two winning percentages in the NHL’s Western Conference this season.
The Avalanche held a slight lead, .823 to .781.

Once the teams hit the ice for the first time as Central Division foes, under the NHL’s new realignment, the difference was more drastic than a few percentage points.

The Blues walloped Colorado and that encompassed more than the score. In their 7-3 victory, the Blues had a punctuating second period, netting four goals to blow the game open and punching out three Avs to blow off some steam.

Alexander Steen netted two of the seven tallies, T.J. Oshie had a career-high four assists and the line, which also includes David Backes, accounted for nine points.

If the idea was to shake off an overtime loss to Phoenix two nights earlier, any remaining remnants were wiped up by the Olympia ice-machine after the game.

“The second period, the way we stuck together, impressed,” Blues coach Ken Hitchcock said. “There were some mistakes, but the way we played in the second period is something you really want to build on.”

The Blues built their record to 12-2-3 and dropped Colorado to 14-4, sending the Avalanche to their first two-game losing streak of the season. The club is 3-0-1 on the current five-game homestand, which wraps up Saturday against Carolina.

Only 14,190 showed up Thursday night for a meeting between teams who have played three and four games fewer than many clubs in the NHL.

For one period, the game unfolded as tightly as anticipated, with the clubs trading first-period power-play goals for a 1-1 score at the first intermission.

The Blues’ Derek Roy recorded his fifth goal of the season, on a nifty feed from Oshie, a theme for the night. Oshie had four assists to increase his season total to a team-high 14.

“He’s a great passer,” Roy said. “He’s deceiving with his hands and he makes plays inside tight.”

The Blues were facing a Colorado club Thursday that hadn’t allowed a power-play goal on the road this season, bringing a 20-for-20 mark into Scottrade Center.