Washington went 0 for 8 on the power play and lost its fourth straight -- the team's longest skid since Oct. 6-12, 2009.
"If your best players aren't your best players, you're not going to have success," Boudreau said. "You have to get production out of your best players, and it's not happening for us right now."
In the first period, the Capitals were denied on all five power-play opportunities, including a two-man advantage that lasted for nearly two minutes.
After that, Washington made it easy for Vokoun to complete his 41st career shutout.
"You could see at the end of the first period, we started to try to do things as individuals instead of collectively," Boudreau said. "When that happens, it's tough."
It was the third time in 11 games the Capitals were blanked. A year ago, Washington led the league in goals and wins.
"Alex [Ovechkin] has two goals in 11 games, [Alexander] Semin hasn't scored in seven or eight games. Mike Green hasn't gotten a goal in I don't know how many games," Boudreau lamented. "Same thing with Nick Backstrom; he scored in the St. Louis game which was five games ago, but that was it. You can go farther down with Brooks Laich and Mike Knuble."
Ovechkin couldn't deny Boudreau's assertion.
"It feels pretty bad," he said. "We had, I think, 20 minutes of power play and we didn't play how we have to play. We played so casual, and you can see the results."
Much of the credit goes to Vokoun, who repeatedly frustrated the Capitals during the pivotal first period.
"Thankfully we survived that first period with hard work and a little luck," Vokoun said. "It gave us momentum. After that, I think we played pretty well."
"That means we can beat anybody in this league," Frolik said. "I think that's important for our confidence."
The Panthers went up 1-0 when Frolik tapped a rebound past Semyon Varlamov with 1 second left in the second period. Varlamov had already stopped two attempts before Frolik got his stick in the crease and lifted the puck over the fallen goalie.
"I came in between periods, and everyone was hanging their heads," Boudreau said. "We were down 1-0. My job at that time is to let them know that they're good and don't feel sorry for yourself."
His effort didn't work. The Capitals were listless in the third period, and the Panthers pulled away.
"Once it was 2-0 you could see the shoulders sagging and everything on the bench and they didn't believe they were going to come back," Boudreau said.
Santorelli's goal, with 2:34 left, snapped a 2-for-53 drought for the Panthers on the power play.
At game's end, those who remained in the sellout crowd jeered the home team.
Boudreau couldn't blame them.
The Capitals have allowed only one first-period goal in eight games. ... Vokoun is 8-12-1 against Washington. ... Florida has killed 20 of its opponents' last 22 power plays.