Josh Norris, Chris Tierney and Nikita Zaitsev scored third-period goals as the host Ottawa Senators earned a 3-1 comeback victory over the Calgary Flames on Wednesday. Filip Gustavsson made 28 saves for the Senators. Gustavsson, who is fourth on Ottawa’s depth chart, has two career NHL starts and has won both of them. The Senators are last in the North Division and easily are the worst in the goals allowed, but have won five of seven clashes with the Flames, including consecutive home games against Calgary. Mark Giordano scored Calgary’s lone goal and Jacob Markstrom stopped 28 shots for the Flames, who have dropped three consecutive and have managed only two goals in that swoon. It is the first time this season the Flames lost despite leading through two periods. The Flames controlled play until the final frame and paid for their inability to pull away when Norris tied the game. Evgenii Dadonov took the puck from Flames defenseman Chris Tanev at the end boards and threaded a pass to the slot for Norris to convert at 4:48 of the third period. It was his third goal in four games and eighth on the season. The Senators took the lead when Tierney scored his second goal in as many outings. Markstrom stopped Thomas Chabot’s shot, but Tierney - who scored his first goal in 30 games to net the winner in Monday’s meeting - pounced on the rebound with 7:59 left in regulation. Zaitsev added an empty-net goal with 76 seconds remaining, his first goal of the season, to round out the scoring. Giordano tallied for the goal-starved Flames to give them a 1-0 lead. Sean Monahan’s work deep in the Ottawa zone resulted in Giordano unloading a point shot that ricocheted off a defender and into the net at 13:37 of the middle frame for his fourth goal of the season. With his assist, Monahan moved into the fourth spot on the franchise’s all-time list for career points among centers with 432. He now trails only Joe Nieuwendyk (616), Kent Nilsson (562) and Guy Chouinard (529) on that list.