The Capitals look to avoid a third straight defeat as they host the Hurricanes in the opener of a home-and-home set Tuesday night.
Washington (10-13-1) had won eight of 11 before a lack of discipline led to back-to-back losses against the teams from New York.
Two double-minor penalties in less than four minutes of the third period Saturday resulted in two power-play goals by the Islanders in a 5-2 loss.
After saying referees needed to show his team more respect before the Caps' next game, Alex Ovechkin was cited for two penalties within seconds without a stoppage in play in the second period against the Rangers on Sunday. New York scored on the delayed call of the first penalty and added another goal with Ovechkin in the box en route to a 4-1 victory.
"It's frustrating," forward Troy Brouwer told the Capitals' official website. "It shows you how dependent this league is with the power play and how games are changed as a result of special teams.
"The nights where we're out-chancing them with power plays, those are the nights that we're winning. When we're parading to the box all the time, we don't have a hope."
Washington killed 30 of 35 penalties in the 11 games before the Islanders and Rangers went a combined 3 for 8 with the man advantage.
The Capitals were 1 for 6 on the power play and struggled offensively in the two defeats after averaging 3.7 goals in the previous 11.
With half the season done, Washington is seven points out of the final playoff spot in the Eastern Conference.
"Two tough losses because of untimely penalties," said Brouwer, held without a point Sunday after recording four in the previous three games. "If we continue to play the way we have in the past 12 or 15 games or so, I think we will be in the playoff picture in the end."
Washington has fallen eight points behind the Hurricanes (14-9-1), its Southeast rivals who have averaged 4.2 goals while winning five of six.
"We've played well. We've had some consistent points where we've come to play for several games in a row," Carolina defenseman Tim Gleason told the team's official website. "I think that's key in a shortened season, and that's something we have to continue. That will get us to the point where we want to be."
Jiri Tlusty had two goals and an assist while Alexander Semin added one with two assists as Carolina defeated New Jersey 6-3 on Saturday. The Hurricanes rebounded from a 4-2 loss to Montreal on Thursday.
Tlusty has six of his team-leading 13 goals and three assists over the last six games, while Semin has four goals and 11 assists in eight games.
Eric Staal had two assists Saturday and has eight to go along with three goals in the past six.
Braden Holtby made 33 saves to help Washington snap a three-game skid against Carolina with a 3-0 home win Feb. 26. Though Holtby has stopped 73 of 74 shots to win both career starts versus Carolina, he was pulled after giving up three goals on 19 shots Sunday.
Ovechkin, who failed to record a point over the weekend, has one assist in his last four against the Hurricanes.