SUNRISE, Fla. -- On a night full of offensive highlights, the ugliest goal was the most crucial.

Jonathan Marchessault scored the tiebreaking goal with 6:03 left in the third period to lead the Florida Panthers past the Ottawa Senators 6-5 on Tuesday night at the BB&T Center.

Marchessault took advantage of goalie Mike Condon, who tried to clear the puck behind his own net but failed, moving it just a couple of feet. Marchessault scored unassisted into an empty net for his 15th goal of the season.

"We knew (Condon) was playing the puck a lot," Marchessault said. "I tried to force him to do a play. (The puck) was just rolling on him, and I got a little lucky."

Condon knew he made a mistake.

"I tried to make a quick play and beat the forechecker," Condon said of Marchessault. "It came off my blade wrong or I didn't have a strong enough forehand.

"It was a tough way to end that one."

Jason Demers added an empty-net with 35 seconds left to give Florida a season-high six goals.

The Panthers, who rallied from a 4-2 second-period deficit, hung on after Ottawa's Derick Brassard scored with 12.5 seconds left.

Florida (22-19-10) earned a key win over the Senators (26-16-6), who are four points ahead of the Panthers in the Atlantic Division.

In the first game for either team after the All-Star break, Florida defenseman Michael Matheson and Ottawa center Ryan Dzingel each scored two goals.

Matheson highlighted a big night for Florida's defensemen, who scored four of its six goals and have 28 on the season. Florida defensemen totaled only 27 goals all of last season.

Both goalies -- Condon (28 saves) and Florida's Roberto Luongo (36) -- were under siege all night. Oddly, none of the 10 goals came on the power play. Ottawa was 0 for 4 with the man advantage and Florida 0 for 3.

Florida got on the board first. With 2:24 expired in the first period, Matheson chipped the puck in, chased it down and shot on goal. Condon blocked the shot but Ottawa defenseman Chris Wideman accidentally kicked the puck in with his right skate.

"He was flying tonight," Florida defenseman Mark Pysyk said of Matheson.

Ottawa tied the score with 4:58 gone in the first. On a three-on-two rush, Dzingel received a stellar cross-ice pass from Kyle Turris and beat Luongo with a high shot at point-blank range.

Florida took a 2-1 lead 24 seconds later. After an Ottawa turnover, Florida had its own three-on-two rush. Michael Sgarbossa got the puck to Derek MacKenzie, whose cross-ice pass left Pysyk with a tap-in goal.

Ottawa tied the score 2-2 with 8:54 left in the first. After Bobby Ryan's shot from the left circle went wide, Dzingel scooped the rebound off the end boards and wrapped the puck into the net before Luongo' could kick out his left leg.

The Senators capped a wild, five-goal first period with a score from Wideman, atoning for his earlier mistake. With 31 seconds left in the period and the teams skating four-on-four, Wideman walked in after a pass from Erik Karlsson and scored on a slapshot.

Ottawa made it 4-2 with 2:19 expired in the second period. Luongo made a save, but it created a long rebound to Karlsson at the right circle. Karlsson's wrist shot beat Luongo, who was screened on the play.

Florida scored only 18 seconds later as Colton Sceviour scored on a backhander after the puck bounced off the end boards.

"It was a big relief," Sceviour said of his first goal since Oct. 30.

Matheson's second goal, which came with 9:53 expired in the second period, tied the score 4-4. Sgarbossa won a faceoff and got the puck to Matheson, who unleashed a low, hard shot from the left circle.

Florida pulled away in the third period, and Ottawa, despite attempting 60 shots, came away with no points.

"It was a typical after-the-(All-Star) break hockey game," Ottawa coach Guy Boucher said. "You don't want it to be that, but I was expecting that. Both teams gave up too many goals."

NOTES: Senators G Mike Condon made his 16th consecutive start and tied a franchise record for goalies by making an appearance in 25 consecutive games. ... Panthers backup G James Reimer was supposed to start, but got the night off after he and his wife welcomed their daughter into the world at 4 a.m. ... Florida waived D Dylan McIlrath and C Paul Thompson. ... The Panthers are awaiting the return of top-line forwards Aleksander Barkov and Jonathan Huberdeau. Barkov (back) hasn't played since Dec. 28 but should be back in February. Huberdeau (ankle) has been hurt all season but should return in March. ... Ottawa's point percentage is its best since 2007, when the Senators made it to the Stanley Cup Final for the only time in franchise history.