Marchand is the 102nd player in NHL history to reach the milestone, and the 12th active. The 37-year-old, who has 14 points (eight goals, six assists) during a nine-game point streak, has 435 goals and 565 assists in 1,116 career games.
Sam Reinhart had two goals and an assist, Eetu Luostarinen had a goal and two assists, Seth Jones had a goal and an assist, and Anton Lundell had three assists for the Panthers (9-7-1), who have won three of four. Daniil Tarasov made 37 saves for his first win of the season (fifth start).
Rasmus Sandin had a goal and an assist for the Capitals (8-8-1), who went 1-3-0 on a four-game road trip. Logan Thompson made 22 saves.
Brandon Duhaime, who was born in Coral Springs, Florida, gave the Capitals a 1-0 lead at 8:25 of the first period. Florida turned the puck over in the offensive zone, and Sandin sent a shot toward the net from above the right circle that Duhaime redirected over Tarasov’s right shoulder.
It was his third straight game with a goal after he didn’t score in the first 14 this season.
Evan Rodrigues scored his 100th NHL goal 28 seconds later to tie it 1-1. He beat Thompson with a slap shot from the edge of the right circle after Niko Mikkola’s shot from a sharp angle produced a big rebound.
Cole Schwindt gave Florida a 2-1 lead at 3:05 of the second period when he redirected a point shot from Gustav Forsling.
Reinhart made it 3-1 at 14:41 with a power-play goal, knocking in a rebound with his backhand from the edge of the crease.
Justin Sourdif, who was traded to the Capitals by the Panthers on June 26, scored 52 seconds into the third period to cut it to 3-2. He tapped in a backdoor pass from Jakob Chychrun at the right post.
Reinhart responded to push the lead to 4-2 at 4:54. He kicked a pass from Lundell, who was behind the net, to his stick in front, calmly pulled it back to avoid a poke check from Ryan Strome, and scored over the right pad of Thompson.
Jones scored his 100th NHL goal on a power play to make it 5-2 at 9:47. He roofed a shot from above the right circle that went in just under the crossbar.
Sandin cut it to 5-3 with a point shot through traffic at 12:40.
Luostarinen scored into an empty net from the neutral zone to make it 6-3 at 18:30. Marchand had the primary assist on the play to reach his milestone.