"It's no fun watching -- I just want to contribute anyway I can," said Horton, the third overall pick in 2003. "I want to be out there with the guys and having fun. And we had fun tonight."
Bryan Muir and Andrew Cassels scored for Washington, which lost its fifth straight. The Capitals were 1-for-7 on the power play -- ranked 29th overall -- and failed to score on a 5-on-3 advantage for 1:21 in the first period.
Washington's Brent Johnson, making his sixth start of the season in place of Olie Kolzig, stopped 33 of 36 shots.
The Capitals' Alex Ovechkin, who leads the league's rookies in goals, failed to score for a season-high sixth straight game. Luongo made a sensational glove save of a wrist shot by Ovechkin with 23 seconds left.
"The puck squirted out to the slot and I knew it was him," Luongo said. "I had a good feeling he would fire it right away and I was able to get a glove on it."
"It was a great play by Luongo on that save," said Ovechkin, who took four shots. "I had lots of chances to score. I have to work hard."
The teams entered the game tied with the fewest points in the Eastern Conference at 18. They played before an announced crowd of 10,092, which was the smallest in Florida's six-plus seasons at the Bank Atlantic Center. In reality, the crowd was about half that number.
"It helps when you have a noisy building," Capitals coach Glen Hanlon said. "(But) they say when you don't score on a 5-on-3 it will come back to haunt you."
The Panthers took a 3-1 lead on Jokinen's power-play goal 4:19 into the third period. Johnson, screened by several players, failed to stop Jokinen's floating wrist shot from just inside the blue line. It was Jokinen's 11th goal.
Washington got within 3-2 at 7:24 when Cassels put the puck past Luongo while standing among seven players in front of the net. It was Cassels' fourth goal.
Muir's power-play goal pulled Washington within 2-1 at 11:20 of the second period. Muir fired a wrist shot from just inside the center blue line for his fourth goal. Luongo, beaten to the stick side, was screened by defenseman Sean Hill.
Horton, who missed 10 games with a sprained knee, gave Florida a 2-0 lead with his eighth goal at 7:25 of the second period. Horton took a pass from Josef Stumpel and wristed a shot from the right circle that beat Johnson high to the glove side.
"I want that one back," Johnson said. "It was a good shot, but he caught me moving."
Weiss deflected Joe Nieuwendyk's slap shot for a power-play goal at 12:26 of the first period. It was Weiss' eighth goal and gave him 14 points in 17 games.
- Referee Don Van Massenhoven dropped the ceremonial puck. Van Massenhoven has been sidelined since being hit in the face with a puck during a game between New Jersey and Florida on Nov. 23.
- The game had been postponed on Oct. 29 due to the aftermath of Hurricane Wilma.
- D Alexei Semenov, acquired from Edmonton on Nov. 19, made his debut with the Panthers.
- Norton scored six goals in a nine-game stretch between Oct. 13-Nov. 1.