CALGARY, Alberta (AP) — David Perron scored twice on the power play Friday night as the St. Louis Blues scored four unanswered goals in the first period and never looked back in a 5-2 victory over the Calgary Flames.

Perron's first of the night at 17:12 of the first period came against Joey MacDonald, who took over in the Flames' net for starter Leland Irving just over four minutes into the game after St. Louis scored on two of its first four shots.

Calgary outshot the Blues 15-5 in the second, but was only able to solve rookie Jake Allen once when Dennis Wideman ripped rising slap shot through a crowd.

The Flames scored again 2:46 into the third when Curtis Glencross was set up neatly by Jarome Iginla.

Rookie Jaden Schwartz, with his first of the season, Patrik Berglund and Alex Steen also scored for St. Louis.