As a rock song mantra suggests, you can’t always get what you want. And in hockey, you can’t always get what you deserve.

Case in point — the Blues’ 3-2 loss to the Calgary Flames on Sunday night.

The Blues wanted to keep momentum going after a 3-0 victory Saturday in Edmonton, and they deserved to be rewarded for outplaying the Flames throughout — outshooting them 38-17. But Calgary netminder Mikka Kiprusoff would not cooperate.

Trailing 2-0 midway through the game, the Blues got goals from T.J. Oshie and Vladimir Sobotka to tie the contest in the third period.

But a sloppy goal the Blues allowed Jarome Iginla to score late in the final period shot down the comeback. He appeared to have been slowed on a breakaway but managed to get the puck past goalie Jaroslav Halak anyway.

“Their third goal was a weak goal, so what are you going to do?” Blues coach Ken Hitchcock asked. “We played hard and competed. But for us to get moving ahead, our power play has to become a force again.”

The Blues went 0 for four with the man advantage.

“We’re giving up too many opportunities that we work to earn,” Hitchcock added. “It’s something we want to address. If we continue to play good five-on-five hockey, we’ll be all right.”

The Flames (12-14-4 ) are not currently a playoff-caliber opponent. Coming off a rough 5-1 loss at Columbus, Calgary has not won a road game all month.