Giordano took a long slap shot from near the Edmonton blue line and the puck scooted underneath Nikolai Khabibulin with 14:16 gone in the middle frame, giving the Flames a 2-1 lead and all the scoring they would need.
The tally came only 4 minutes after Ryan Jones had pulled the Oilers into a 1-1 tie with his ninth goal of the season. Dustin Penner got control along the boards and Tom Gilbert put the puck on Jones's stick for a one-timer past Mikka Kiprusoff on the play.
Tim Jackson also scored for the Flames and Kiprusoff turned aside 16 shots as Calgary reached the .500 mark for the first time in nearly two months.
Khabibulin stopped 28-of-30 shots in absorbing the loss, the Oilers' eighth in nine games.