Leading 1-0 after the first period, the Flames increased the lead to two goals at 3:38 of the second. Mikael Backlund's shot missed the net but the puck caromed sharply off the end boards and out the other side where Giordano had jumped up into the play and one-timed it in the short side as Alex Stalock scrambled across.
The ninth goal of the season for the Flames captain extends his career-high scoring streak to eight games (four goals, four assists).
The Flames, who are enjoying their longest winning streak since reeling off five victories in a row in March 2012, are a perfect 4-0-0 with one game to go on a five-game homestand.
Eriah Hayes, with his first NHL goal, was the lone Shark to solve Ramo. San Jose (34-15-6) has lost three straight.
The Sharks entered the game on two straight shutouts after losing 1-0 to Jonathan Quick and the Los Angeles Kings on Monday, and 3-0 in Edmonton on Wednesday, thanks to Ben Scriven's record-setting 59 saves.
San Jose was held to eight shots in the first period but racked up 13 in the second, including multiple chances to score on Ramo.
The Sharks finally got on the scoreboard 46 seconds into the third and this they would not be denied.
After Chris Butler lost the puck in front of his own net, a quick passing sequence with Tommy Wingels and Patrick Marleau set up Hayes less than 15 feet away and he buried a quick shot over Ramo's glove.
It was the 13th game for Hayes, who was recalled from Worcester (AHL) on Jan. 4 and made his NHL debut the next day.
That goal ended a stretch of 160 minute, 36 second scoreless drought for the Sharks, who racked up 103 shots on goal before Hayes connected.
The Flames restored their two-goal cushion after Ladislav Smid's shot went wide and bounced out the other side for Joe Colborne, who directed it in front for Monahan. The rookie redirected it out of the air for his team-leading 15th goal.
Stalock, who had only surrendered one goal on 65 combined shots in his previous three starts, got the nod in net for the Sharks, and finished the night with 26 stops as his record fell to 7-4-0.
Ramo got the start for the Flames for his fifth start in his last six games. Ramo was solid all night to improve to 11-10-4.
Calgary opened the scoring at 8:41 of the first period on a nice rush by Backlund. Darting down the wing, he got around Matt Irwin to get a shot on goal. Stalock stopped that one but Stempniak was right there to poke in the rebound.
After a eight-game stretch in which they amassed only six goals, four of them coming in one game, the Flames have racked up 26 goals in their last nine games.
Notes: The Sharks record for being shutout was 190:22 set in February 2007... Calgary LW Mike Cammalleri (concussion) missed his ninth game. He is back practising with the team and hopes to play Saturday against Minnesota... Tyler Kennedy (lower body) did not play for San Jose. He was hurt Wednesday night in Edmonton... Calgary is 16-9-7 in one-goal games and now 4-18 in games decided by two-or-more goals... Since being converted to a forward, San Jose's Brent Burns has 49 points (23 goals, 26 assists) in 66 games.