Mike Green’s power-play goal with 5:48 left in regulation time gave Washington the home win at the Verizon Center. Alex Ovechkin and Nicklas Backstrom also scored for the Capitals, the seventh seed in the Eastern Conference.
Artem Anisimov and Marian Gaborik scored for top-seeded New York, which won Game 3 in Washington 2-1 in triple overtime.
The Rangers will host Game 5 in two days before the best- of-seven series returns to Washington on May 9.
Ovechkin gave the Capitals the lead on a slap shot with 7:17 left in the first period. Anisimov drew the Rangers even 70 seconds into the second period, but Washington went back in front midway through the period after Backstrom beat Rangers goaltender Henrik Lundqvist with a wrist shot.
Gaborik tied the score less than five minutes later when he took a pass from Anisimov and sent a wrist shot past Braden Holtby.
Washington then won the game with New York’s Carl Hagelin in the penalty box for slashing when Green took a pass from Dennis Wideman and fired a slap shot by Lundqvist from the right circle.
It was Washington’s 10th one-goal game in 11 this postseason, while eight of New York’s 11 playoff games have been decided by a goal.
To contact the reporter on this story: Bob Bensch in London at firstname.lastname@example.org.