Garnet Hathaway had a goal and an assist, and Andrew Mangiapane scored for the Flames, who are 6-1-0 in their past seven games.
"Good intensity out there," Giordano said. "We knew it was going to be like that, they are trying to get that last playoff spot and fighting for every point. We did a great job handling it."
It was the first loss in four games for the Canucks (32-33-10), who are six points behind the Colorado Avalanche for the second wild card into the playoffs from the Western Conference.
"It's deflating any time you lose," coach Travis Green said. "But I do like the way our team played and the intensity in the game."
Brock Boeser scored, and Jacob Markstrom made 28 saves for Vancouver, which is 4-1-1 in its past six games after going 4-10-3 in its previous 17.
"I thought we were competing hard there in the third and getting some chances," Boeser said. "But there were some small details in the game that cost us. We need to clean those up."
Calgary's fourth line of Derek Ryan, Hathaway and Mangiapane generated all three of its goals. The three have combined for eight goals and nine assists in the past six games.
"They've been really good for a long time now, and it's really nice to see them get rewarded," Giordano said. "They are putting pucks in the net it seems like every game for us. And I think their skill is underrated. They all shoot the puck, move the puck to each other, and they have great chemistry right now. It's fun to play with them."
Giordano scored with a one-timer off a cross-ice pass from Ryan to the bottom of the left face-off circle at 9:44 of the first period to make it 1-0.
Hathaway made it 2-0 with 2:52 left in the second period with a backhand from between the hash marks that fluttered past a screened Markstrom.
Boeser scored on a 4-on-3 power play 38 seconds into the third period to make it 2-1 and extend his NHL career-high point streak to nine games (four goals, six assists).
Mangiapane made it 3-1 at 7:25 when he one-timed a cross-ice pass from Giordano to the right hash marks.
"It starts with good communication," Mangiapane said. "If we have a question, we talk and sort it out. We are all good buddies. We sit beside each other on the plane, and we are building good chemistry."
