Weegar gave Calgary a 1-0 lead with 56 seconds left in the first period. Hanley took a wrist shot from above the right circle that Blake Coleman deflected off the right hip of Weegar and across the goal line.
"Those bounces are great, but we owned those chances, we worked hard for those chances, " Weegar said. "The game is quick, so I thought we worked hard and we were on the other side of those bounces."
Flames forward Connor Zary sustained a lower-body injury at 6:34 of the second period and did not return when he collided with Ducks defenseman Drew Helleson.
Helleson received a five-minute major penalty for kneeing and a game misconduct, and Flames forward Jakob Pelletier was assessed a roughing penalty on Helleson.
Calgary coach Ryan Huska did not have a postgame update on Zary, who had to be helped off the ice.
"There was no way he was trying to intentionally hit him with the knee," Anaheim coach Greg Cronin said. "I don't think his skates ever came off the ice. He's trying to play him 1-on-1 and hit him with his shoulder."
Killorn scored in the final second of the ensuing 4-on-4 to tie it 1-1. Isac Lundestrom carried the puck from the Anaheim zone before dropping a pass for Killorn, who skated to the high slot and scored on a wrist shot at 8:34.
"It's tough to see a guy go down," Huberdeau said. "We didn't score on the power play, but I think we generated some momentum."
Kadri put Calgary back ahead 2-1 at 12:44. He cut down the middle and scored on a redirection of Weegar’s centering pass from along the wall.