Mark Giordano scored at 4:30 of the extra period as the Flames survived a two-goal deficit and the loss of leading scorer Jarome Iginla to beat the Florida Panthers 5-4.
The Flames forced OT with two goals in the game's final 3:06, capped by rookie David Moss's tying goal at 18:22.
Calgary was forced to rally without Iginla, who fell to an undisclosed injury halfway through the second period.
"It's tough to fill a guy's spot, a guy like Jarome, but the guys did a great job of stepping up in the last five minutes and it continued into overtime," said Giordano.
Iginla's status remains unclear, and it's not known exactly when he suffered the lower body injury. It was originally thought that the Flames captain was hurt in a fight with Panthers defenceman Bryan Allen, though the injury may have actually occurred seconds before, when Allen checked Iginla into the side boards.
Allen had drawn the ire of the Flames players five minutes into the game when he flattened forward Chuck Kobasew just inside the Calgary blue-line, a check that left Kobasew flat on the ice for several minutes. Kobasew also did not return, though team officials said he was held out only for precautionary reasons.
Whether it was retaliation for the Kobasew hit or some other reason, seeing Iginla drop the gloves is a common occurrence for his Flames teammates.
"You certainly don't want a guy that has 53 points breaking his hand but that's Jarome, that's his game, and you can't take that away from him," said Jamie McLennan, who made 38 saves in his first home start of the season.
"There are different leaders and different warriors in this league and when you have a guy that's third or fourth in the league in scoring and he's stepping up and fighting for his team, that shows his character."
Iginla, who entered the night fourth in the NHL in scoring with 52 points, had his 23rd goal of the season in the first period.
Without Iginla on the bench, Calgary saw its 2-1 third period lead evaporate on two goals by Rostislav Olesz and the first NHL goal for David Booth. That cued a wild Flames comeback.
Byron Ritchie got Calgary back within one at 16:54 and David Moss took Jeff Friesen's pass and moved out front before tucking a shot inside the far post to tie it.
The late rally came immediately after Flames coach Jim Playfair called a time-out following Florida's fourth goal.
"There was no emotion on the bench for a period of time and we let them back in the game and take the lead," said Ritchie. "It's huge to lose two lose two right wingers like that, who log a lot of minutes, so it was time for some other guys to step up. It took us a little while longer than we wanted to but we got it done."
Alex Tanguay also scored for Calgary (19-15-4). Bouwmeester had the other goal for Florida (15-20-7).
Making just his second start in the last 10, Auld finished with 24 saves and blamed himself for the loss.
"It sucks," said Auld. "The guys score for me and I don't do my job at my end. Probably more than any game I've ever played, I felt that game was more my fault than anything else."
Notes - Florida and Calgary entered the night as the only two teams without an overtime or shootout victory. ... After three games on the Flames' second line, Tanguay returned to the top line alongside C Daymond Langkow and Iginla. ... Florida put LW Gary Roberts on injured reserve Thursday afternoon and recalled forwards Janis Sprukts and Anthony Stewart from Rochester (AHL). Both were in the line-up against Calgary. ... Including the playoffs, Calgary G Miikka Kiprusoff had started 86 of the last 88 games at the Pengrowth Saddledome dating back to Feb. 10, 2004, when he returned from a knee injury.