WASHINGTON — When you put the defending President’s Trophy winners up against a team in transition in the fifth game of the season, the results should not be surprising.

But Saturday night they were.

Picked by almost everyone to win the Metropolitan Division and compete with Tampa Bay for the Eastern Conference championship, the Capitals, who entered undefeated in regulation, rolled to a two-goal lead over the Rangers at Verizon Center in the first period. But the Blueshirts scored three straight goals, including the tying and go-ahead goals from rookie Jimmy Vesey, and the Rangers skated to a 4-2 win.

During that second-period rally, Brandon Pirri’s wrister from high between the circles off a rush beat Braden Holtby glove side and then Vesey scored two goals in a 3:00 span — first on a power play after a pass from Rick Nash stationed in front at 11:22, and then on a great individual effort at 14:22. Vesey skated down the left side and around defenseman Karl Alzner with the puck. He cut to the net to deposit a backhander past Holtby for a 3-2 lead.

Trailing 2-1, the turning point was clearly a four-minute penalty kill, when Mika Zibanejad’s stick bloodied T.J. Oshie’s lip at 4:08.

“When you get in a situation like that against Washington, it can go one way or another,” defenseman Marc Staal said. “They get two quick ones, or we can battle through it and get a big kill and we gained some confidence after that.”

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The three goals were remarkable because the Capitals had allowed just five goals — only two at even strength — in four games as Vesey, the rookie free agent out of Harvard, continued to impress.

“He’s got a lot of self-confidence and it was good to see him finish on the first one,” coach Alain Vigneault said. “The second, that was just a power move.”

In the third, the Rangers worked hard to break up plays and block shots. In one sequence with about 12 minutes left, after Lundqvist stopped Evgeny Kuznetsov, defensemen Kevin Klein and Ryan McDonagh blocked tries by Alex Ovechkin and Oshie. Capitals coach Barry Trotz pulled Holtby for an extra attacker with 1:37 left and called a timeout with 57.9 seconds left.

Lundqvist, who now is 11-3-2 against the Caps in his last 16 decisions, made the lead stand with 26 saves and the Rangers have won nine of the last 12 here. Nash sealed the victory with an empty-netter with 5.9 seconds left and the Rangers upped their record to 3-2. The Caps dropped to 3-1-1.

The Blueshirts had struggled early with Lars Eller finding position while matched against Brady Skjei in front of the net to tip Brooks Orpik’s shot past Lundqvist at 1:09 of the first period, and the Caps continued to control play for most of the period. The Capitals also killed two penalties, although the second came after Ovechkin had lifted them to a 2-0 advantage when he skated toward the right circle and used Staal as a screen to fire a shot past Lundqvist at 14:49. Although the Rangers had 13 shots on Holtby, the Caps were winning battles all over the ice.

“Every game we’ve played, we’ve faced some adversity,” Vesey said. “After the first period, we just talked about using our speed to our advantage, to get in on the forecheck. We have four lines that can really skate. We just wanted to keep using our speed.”