Kunin made it 3-1 at 12:30 on the power play when his one-timer from below the right circle was pushed across the goal line by Flames defenseman Chris Tanev after Wolf’s initial save.
Backlund cut the lead to 3-2 at 19:40 with a wrist shot from the right circle through traffic that deflected in off Sharks defenseman Calen Addison.
Zadina put the Sharks ahead 4-2 at 4:38 of the third when he redirected a Nico Sturm shot that looped over Wolf into the net. He scored again 37 seconds later with a wrist shot over Wolf's glove to make it 5-2 at 5:15.
"It felt pretty good, obviously," said Zadina, who had three points (one goal, two assists) in his previous 18 games. "We haven't scored as a line in a little bit, but we got rewarded for the work we've done recently."
Kunin scored a wrist shot from the bottom of the right circle on a breakaway following a Blake Coleman turnover to push it to 6-2 at 15:30.
Kuzmenko tipped a Tanev point shot past Blackwood for the 6-3 final at 16:40.
"You think it's going to be easier than other games, and it's not," Flames forward Jonathan Huberdeau said. "At the end of the day, they're still a good team, they're in the NHL. They came out and had a bad start, but they can play. They worked hard tonight, and we just weren't ready to play."
NOTES: Bailey’s three points are an NHL career high. … San Jose matched its season high for goals. ... The Sharks are 17-for-17 on the penalty kill in the past six games. ... Blackwood is 5-1-1 with a 2.25 goals-against average and .931 save percentage in his past seven starts. ... San Jose's Marc-Edouard Vlasic had an assist and played 18:34 in his 1,270th NHL game, tying Rob Blake for 25th in League history among defensemen. ... Huberdeau had an assist on Kuzmenko's goal for his 700th NHL point. Huberdeau, who has 221 goals and 479 assists in 803 games, is the third player from the 2011 NHL Draft class to reach the mark (Nikita Kucherov, 822; Johnny Gaudreau, 718).