Already down one game in a best-of-seven series that they are expected to win, the Capitals made a risky goaltender change to start Game 2 on Saturday afternoon.

Washington coach Bruce Boudreau turned to rookie Simeon Varlamov, a 20-year-old Russian who had started all of five professional games in North America.

It was a calculated roll of the dice after veteran starter Jose Theodore struggled in Game 1. Varlamov had played against grown men in the Russian Elite League as a teenager. He also had international experience with his country’s national team. But the Stanley Cup playoffs are a whole different story.

And while Varlamov did fare much better than Theodore had in the opener, the result was still the same for the Caps. Forward Ryan Callahan scored a first-period goal for the Rangers, who took a 1-0 victory in an Eastern Conference quarterfinal at Verizon Center and a commanding 2-0 series lead.

The scene now shifts to Madison Square Garden in New York for Games 3 and 4 with the pressure squarely on Washington, which entered as the No. 2 seed and favorite and now desperately needs a win to get back into the series.

“We don’t really have an option,” said Caps defenseman Brian Pothier, inserted into the lineup for Game 2. “We need to perform in the first period on Monday. That’s our focus right now. We have to practice well and move on to Game 3.”

Varlamov had the least experience of any Stanley Cup playoff starter since Miikka Kiprusoff for San Jose in 2001 and was just the fourth rookie in Caps’ history to start in goal for a playoff game — the others were Jim Carey, Byron Dafoe and Bob Mason. Only 18 other goalies in NHL history have started a playoff game before their 21st birthday.

”Well, of course I want to play,” said Varlamov through an interpreter. “It was my dream since childhood. It is not a secret.”

He replaced Theodore, who allowed four goals in the first game on just 21 shots. Boudreau was coy for two days about who would be his starter for Game 2 and fans and media found out about the switch only when both teams came out for warmups about 30 minutes before the puck dropped. The players themselves, according to forward Tomas Fleischmann, learned about the switch in the dressing room about an hour before the game. Varlamov fared well — although he was tested far less often than New York goalie Henrik Lundqvist. But Caps coach Bruce Boudreau was less forthcoming about Varlamov’s status for Game 3 in New York or even about when he decided a switch was necessary.

“No, I’m not going to go through the mechanics [of the change],” Boudreau said. “I made the decision and I stuck by it and that’s the end of it.”

Boudreau said he will meet with his coaching staff on Sunday after an optional practice and make a decision on a starter for Monday’s game then. But Varlamov certainly appeared to earn another shot with his play, stopping 23 of 24 New York shots on goal.

“I thought he played well, said Boudreau. “I didn’t think anything could be done on the first goal [by Callahan]. And he made a really good save about three minutes after that. I was very happy with his game.”

Boudreau also noted that Theodore took the change “like a professional.” Varlamov said the veteran walked over to him after warmups and gave him a quick pep talk. Theodore told his rookie replacement how he, too, had started in the postseason as a young goalie. He was just 21 when given the assignment for his hometown Montreal Canadiens in two 1997 playoff games against the New Jersey Devils.

The Caps have not been down 2-0 in a playoff series since the first round in 2000 against Pittsburgh — a series they lost 4-1. They have never recovered from a 0-2 start the four times it has happened in franchise history. But they were down 3-1 to Philadelphia in last year’s first-round series and forced a Game 7, losing at home in overtime.

“We can’t get down. We have to stay up,” said defenseman Mike Green. “Otherwise it’s going to make it even tougher on ourselves. We will be fine. We just need to change a few things that are costing us here.”

Rangers goalie Henrik Lundqvist has stopped 72 of the 75 shots he’s faced through two games. He was helped in the third period when Caps forward Alex Ovechkin rang a shot off the crossbar. Washington – with the league’s second-best power play during the regular season – is 2-for-10 in the series and has just one even-strength goal.

“I know our team will never give up,” Ovechkin said. “It’s a war right now. We fight. We fight. We play hard. But we lose a game.”

Caps notes

» Game 3 of best-of-seven series is Monday night in New York at Madison Square Garden. Start time is 7 p.m. with the game televised on Comcast SportsNet.

» The Caps again outshot New York in the first period, 13-6. But they still trailed 1-0 at the first intermission after Rangers F Ryan Callahan finished a 2-on-1 break pass from teammate Markus Naslund and beat G Simeon Varlamov with a wrist shot.

» The Rangers earned the first four power plays of the game. But unlike Game 1 – where they scored twice with the extra man – New York was 0-for-5 on the afternoon.

» Caps F Alex Ovechkin led his team in shots (6) and hits (5) for the second game in the series.

» The Caps were last shut out in the playoffs on April 13, 2008 when Philadelphia’s Martin Biron pulled the trick. It was Game 2 of that series as well. Washington has been shut out 10 times in playoff history. But Saturday’s game was the first time they had ever lost a postseason game 1-0.

» The Rangers have blocked an astounding 50 Washington shots in two games.

» Caps coach Bruce Boudreau on his team’s inability to get directly in front of Lundqvist and create traffic: “Hey, listen – we’re trying to get there. Their defense is doing a hell of a job in blocking us out. We talk about getting to the front of the net, getting some rebounds. But we’re going for them and he’s kicking them by us. So it’s not like we’re just sitting there saying we’ll just take shots from the side. I thought we tried like hell to get [to the front of the net].”