"It's awesome," Backstrom said of Ovechkin's 500th assist. "It's great. I've been playing with him for a long time and I'm just happy for him. He's a great hockey player. He can do it all. I think it's just a nice milestone for him. A lot of guys see him as a goal scorer, but he's a good passer, too."
Ovechkin assisted on Backstrom's power-play goal in the first period. John Carlson and Brett Connolly each scored, and Evgeny Kuznetsov had two assists for Washington (29-15-5), which ended a three-game losing streak. Kuznetsov left the game midway through the third period with a lower-body injury.
Braden Holtby made 32 saves for the Capitals.
Washington, which had been 0-1-2 since its five-day break, won for the first time since Jan. 12.
"We had a good week of practice," Carlson said. "We finally started feeling good, now we take another break (for the All-Star Game). We'll have practice when we get back and right back at it. There'll be no time to wait around and give ourselves a couple games to feel good. We've got to come back and start playing real well right away. The season is coming down to the wire and all these points mean so much."
Denis Malgin scored twice for the Panthers (19-22-6), who lost their third in a row and are 2-6-1 since their season-best five-game winning streak.