The Capitals try to end a dismal skid when they host the Panthers on Tuesday night in the season-series finale.
Washington (26-39-14) has been eliminated from the playoffs for the third straight season while Florida (34-30-15) is still mathematically alive. The Panthers are 12th place in the Eastern Conference, but will likely miss the postseason for the sixth consecutive time as they trail eighth-place Montreal by five points with three games left.
The Capitals have lost six straight games, including a 5-2 defeat to Tampa Bay on Saturday. The turning point came when second-leading scorer Alexander Semin took a penalty for closing his hand on the puck, leading to a Lightning power-play tally and two-goal lead.
Semin, who is second with 38 goals and 73 points, played just two shifts in the final period.
"It's unfortunate for Alexander, because it kind of comes to a head, but we have to address taking penalties," said Capitals coach Glen Hanlon, who held a team meeting after the loss. "When we play so well in large parts of games, we just can't afford to do those things."
The Capitals have lost five straight meetings with the Panthers, after winning the first two this season
Martin Gelinas scored his second goal of the game in overtime on Friday to give Florida a 3-2 victory over the Capitals on Friday. The victory capped a three-game winning streak for the Panthers, who then fell 4-3 in overtime to Carolina on Sunday.
Panthers goaltender Ed Belfour gave up two goals in with less than 8 minutes to play in regulation, then was penalized with Bryan Allen 66 seconds into the extra session. Florida lost when Ray Whitney scored on the power-play at 1:30.
"He embellished it as much as he could," Allen said, referring to Carolina's Eric Staal hitting the ice that led to his hooking penalty. "It's embarrassing the way they play the game. They're looking for the easy way out, taking dives and looking for the cheesy call."
Florida's Jozef Stumpel scored twice in the opening period to set a career high with 23 goals on the season. He has four goals and five assists in seven meetings with Washington this season.
Panthers leading scorer Olli Jokinen, who had two assists Sunday, is riding an eight-game point streak with six goals and 11 assists during that span. He comes into this contest with 37 goals and 49 assists, and needs two goals and three assists to set new career highs.
Belfour is 22-6-0 with two ties and a 2.37 goals-against average in 31 career games versus the Capitals.