SUNRISE, Fla. -- Jonathan Marchessault scored the go-ahead goal with 6:03 left, rookie defenseman Mike Matheson had two goals and the Florida Panthers defeated the Ottawa Senators 6-5 at BB&T Center on Tuesday.
Marchessault had the game-winning goal in the Panthers last game before the All-Star break when he scored in overtime in a 2-1 victory against the Tampa Bay Lightning.
"He just keeps scoring big, big goals for us," Panthers coach Tom Rowe said. "He's fearless out there and he's constantly pressuring guys in the offensive zone and taking advantage of it."
WATCH: All Senators vs. Panthers highlights
Matheson had his first multigoal game in 53 NHL games. He had a team-high seven shots.
"Just try to help any way I can," Matheson said. "I think the past few games I've been struggling a little bit to bury the chances that I've been getting, so it's nice to finally have them go in."
Roberto Luongo made 36 saves and became the fifth goalie in NHL history to reach 450 victories. Luongo, who was 0-3-1 in his previous four starts, stepped in for projected starter James Reimer, whose wife gave birth to the couple's first child Tuesday afternoon.
Video: OTT@FLA: Luongo slides across to deny Ceci with pad
Colton Sceviour ended a 39-game goal drought and Mark Pysyk also scored for the Panthers (22-19-10), who have won the first two games of a four-game homestand. Jason Demers scored an empty-net goal with 34.5 seconds left, and Michael Sgarbossa had two assists.
"The amount of games that we have left and the position that we're in, we don't have very much room for many more losses," Matheson said. "So it's huge to be able to build the momentum going into a break and coming off of it."
Video: OTT@FLA: Matheson rips puck in off faceoff for second
Mike Condon, who made 28 saves, tied a Senators record with his 25th consecutive appearance. Damian Rhodes in 1995-96 also played 25 games in a row.
Ryan Dzingel scored twice for Ottawa (26-16-6), which lost in regulation for the first time in seven games (4-1-2). Erik Karlsson had a goal and an assist and Chris Wideman and Derick Brassard scored.
Video: OTT@FLA: Dzingel notches his second from behind net
"We didn't play a horrible game but I don't think we played nearly as good as we needed," Karlsson said. "I don't think we put our best effort forward today."
Goal of the game
Marchessault's winner came when he took advantage of a miscue by Condon. After Condon fanned on a clearing attempt behind the net, Marchessault backhanded the puck in from the side of the net. "It just rolled right off his stick," Marchessault said. "It came to me. He had his stick on it, but I was just able to squeak it by."
Video: OTT@FLA: Marchessault steals puck and slides it home
Save of the game
Luongo was on his stomach after making a save in the second period, but he kicked his left leg out to stop Tom Pyatt's backhand on the rebound.
Highlight of the game
Matheson passed the puck to himself off the boards at the Ottawa blue line, skated around a defenseman, then shifted the puck to his forehand for a quick shot. Condon made the save, but the rebound went off the skate of Wideman and into the net at 2:24 of the first period.
Video: OTT@FLA: Matheson opens scoring on fortunate bounce
Unsung performance of the game
Panthers forward Vincent Trocheck won 67 percent of his faceoffs (18 of 27). He also had two shots and two hits in 20:57.
They said it
"When you look at the game, I think it was a typical after-the-break pond hockey game. I think both teams were just going after each other. Fluky goals happen and we just have to move on." -- Senators coach Guy Boucher
"It's been a long time. I'd be lying if I said I didn't know how long it had been. I'd been pressing a little bit so it was nice to get one." -- Panthers forward Colton Sceviour on ending his 39-game drought
"We don't want to get into games like that, but it's good that we got the win to prove that we can be in games like that if it gets there. But obviously that's not what we want to do." -- Panthers defenseman Mark Pysyk
Need to know
This was the highest-scoring game involving the Panthers this season. The previous high was seven combined goals, which had happened 14 times. … After missing the morning skate, Reimer rejoined the Panthers to serve as Luongo's backup. … Sgarbossa had his first multipoint game in his 34th NHL game. … Karlsson led both teams in ice time (27:31) and shots (8). … Senators forward Mark Stone had his 100th NHL assist.
Senators: At the Tampa Bay Lightning on Thursday (7:30 p.m. ET; SUN, RDS2, TSN5, NHL.TV)
Panthers: Host the Anaheim Ducks on Friday (7:30 p.m. ET; FS-F, PRIME, NHL.TV)
Video: Marchessault's late goal lifts Panthers to 6-5 win