The teams dealt with two separate delays that left a number of players shaken. The teams were sent to their dressing rooms with 3:37 remaining in the first period as first responders dealt with a medical emergency in the stands as a fan required CPR.
The time remaining in the period was played at the start of the second, but another delay ensued when Vincent Trochek twisted his right leg awkwardly and required a stretcher to be taken off the ice.
''This was one of the weirder games I've been involved in, it was very tough,'' Senators coach Guy Boucher said. ''We all knew they were trying to revive the gentleman, so nobody was thinking hockey there. Our prayers are definitely with the patient and the family.''
Mike Hoffman scored and extended his point streak to 16 games in his return to Ottawa after being traded to Florida, and the Panthers topped the Senators 7-5.
Troy Brouwer, Aleksander Barkov, Jared McCann, Evgenii Dadonov, Micheal Haley and Frank Vatrano also scored for Florida.
Hoffman, who has nine goals and 10 assists in the streak, admitted the goal was special.
''That was a big goal,'' Hoffman said. ''That I was able to do it made it that much more special to put the nail in the coffin. I was excited that I scored, but I guess other people aren't allowed to get excited if you get a goal.''
Juho Lammikko picked up four assists. James Reimer stopped 33 shots and the Panthers beat the Senators for the second time in eight days.
Matt Duchene had a pair of goals for the Senators. Drake Batherson, Zack Smith and Brady Tkachuk also scored.
Craig Anderson allowed six goals on 22 shots before being replaced by Mike McKenna. McKenna gave up one goal on nine shots.
It was a strange game in many ways. The first period was cut short due to a medical emergency in the stands. The remaining time was played at the start of the second, but a second delay ensued when Vincent Trochek twisted his right leg awkwardly and required a stretcher to be taken off the ice.
Trailing 6-3, the Senators made things interesting as Smith and Tkachuk scored and cut the deficit to a single goal at the halfway mark of the third. Ottawa had two power-play opportunities, but were unable to capitalize.
''That's the one positive to come out of the game,'' Smith said. ''We didn't give up. It would have been easy to just coast through the third being down three goals, but we came in the room and we talked and we knew we could come back on these guys.''
Smith admitted it was difficult to get back into the game with the two medical emergencies.
''We tried our best, both teams, to put both incidents behind us and play a hockey game,'' Smith said. ''Those are two things you never want to see.''
The Panthers made it 4-1 when Dadonov banged a puck over the goal line with 0.3 seconds remaining in what was the first period.
Ottawa cut the lead in half early in the second as Duchene scored his second of the game off a great feed from Batherson. Shortly after that, Batherson scored on the power play off a pass from Duchene, who has 15 points (six goals, nine assists) in his last seven games.
Haley, playing in his first game of the season, and Vatrano also scored, ending Anderson's night.
''It wasn't pretty, but at the end it was a gutsy win and points we needed,'' said Haley.
The Senators opened the scoring as Duchene netted his ninth of the season early in the first, but the Panthers answered with three goals for a 3-1 lead in the shortened period.
Brouwer tied the game on a one-timer from the side of the net. A power-play goal by Barkov gave the Panthers the lead, and McCann made it 3-1 midway through the period, scoring on a partial breakaway.
NOTES: Christian Jaros returned to the Senators blue line after being a healthy scratch. Chris Wideman found himself the odd man out.
Senators: At Minnesota on Wednesday.
Panthers: At Tampa Bay on Wednesday.
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