"It doesn't matter who scores, whether it's a young player or an older player, as long as we score goals and win games," Pettersson said.
Matthew Tkachuk and Sean Monahan scored, and Mike Smith made 18 saves for the Flames, who lost their first game with new coach Bill Peters.
Calgary finished 0-for-7 on the power play, failing on a couple attempts to get a shot on goal. Vancouver, 0-for-1 with the man advantage, scored twice shortly after killing a penalty.
"Their penalty kill did give them momentum," Peters said.
Forward James Neal, who had an assist in his Flames debut after signing as a free agent July 2, said the failed power plays cost Calgary the game.
"The power play is crucial, it wins and loses you games," Neal said. "We were getting stuck at the line, we weren't coming with enough speed and we were getting frustrated, and it was sucking energy out of us and deflating our bench."
Tkachuk made it 3-1 at 3:08 on a rebound that caught Markstrom out of position, but the Flames failed to convert a penalty to Virtanen 25 seconds later, and Virtanen scored on a breakaway for a 4-1 at 5:46, 13 seconds after his penalty expired.