BOSTON — Ilya Samsonov, making his first start since May 1, was the Washington Capitals’ unlikely hero for 85 minutes in Game 3 of their first-round playoff series against the Boston Bruins at TD Garden on Wednesday night. The 86th minute foiled the young goaltender.

A miscommunication with defenseman Justin Schultz behind the Capitals’ net allowed Boston’s Craig Smith to pick up a loose puck and beat Samsonov to the post with a wraparound shot, giving Boston a 3-2 win in double overtime and a 2-1 lead in the best-of-seven series.

Game 4 is scheduled for Friday in Boston.

“It looked like one of them went for ‘leave it’ and one went for an outlet pass,” Capitals Coach Peter Laviolette said. “There was just a little bit of a miscommunication. It was a tough break the way the game ended. I thought Sammy played a hell of a game for us. It was just tough the way it ended.”

The miscue came at 5:48 of the second extra period, and it was not the first time Samsonov had made such a mistake this season. Capitals captain Alex Ovechkin snapped his stick on the bench after the goal and appeared to give Samsonov an earful as the teams exited the ice.

Samsonov finished with 40 saves, including 17 in the first extra period, when Boston peppered him to no avail.

“He was huge tonight for us,” Capitals defenseman John Carlson said. “I wouldn’t say anything other than: ‘Keep your head up. There’s a lot more hockey to be played.’ He did a great job for us tonight. If he didn’t stand on his head, we probably wouldn’t have gotten to that point. I think he should know that, but that’s definitely something we’ll talk about.”

The Capitals held a 2-1 lead entering the third period, but Brad Marchand knotted the score with a power-play goal with 8:28 left in regulation. It stayed that way for nearly 35 minutes of hockey before 4,565 at TD Garden found a reason to celebrate in the second overtime.

All three games of the series have gone to overtime, and neither team has held a two-goal lead at any point.

Samsonov was thrust into action for the first time in nearly three weeks after he landed on the NHL’s covid-19 protocol list May 4. He missed the team’s May 3 game against the New York Rangers because of disciplinary reasons.

“We’ve been working to get Sammy back and watching him closely to see how he’s been doing,” Laviolette said. “Why did I put him back? Because he’s been our goaltender all year. Him and Vitek [Vanecek] were the two guys that got us here.”

Ovechkin opened the scoring with a power-play goal 8:21 into the second period. His first tally of the postseason came off a nice feed by Anthony Mantha from behind the net. Less than a minute later, though, Taylor Hall roofed a nifty shot over Samsonov to tie the score at 1.

Nic Dowd gave the Capitals a 2-1 lead at 18:15 with his redirection of Garnet Hathaway’s shot.

Dowd left the game for a few minutes earlier in the period after he blocked David Pastrnak’s blast with his right knee. The fourth-liner, who played a bigger role Wednesday with the absence of Lars Eller because of a lower-body injury, has two goals in the series.

In the third period, Dowd took a crucial high-sticking penalty with nine minutes remaining. Boston, scoreless on its four previous power plays, made this one count when Marchand knocked the puck out of the air during a scrum in front for a crucial equalizer.

Samsonov was the Capitals’ third starting goaltender in their first three games of the series. Washington is only the second team in NHL history to start three different goalies in its first three playoff games, joining the 1986 Winnipeg Jets.

Vanecek started Game 1, but he suffered a lower-body injury and exited in the first period. Veteran Craig Anderson, a 39-year-old who made only four appearances in the regular season, came on in relief of Vanecek and made 21 saves in the series-opening win.

Anderson earned the start in Game 2 with Vanecek still hurt and made 44 saves in Monday’s 4-3 overtime loss. Anderson was a late scratch for Game 3 because of what the team termed “body maintenance.” Vanecek was still unavailable, opening the door for Samsonov with Pheonix Copley listed as his backup. Laviolette said he believes Anderson will be available moving forward.

“We felt it was in his best interest with where he’s at coming off a couple of games with a lot of work to take a maintenance day,” Laviolette said. “It was also, Sammy’s been a guy that we have counted on the entire year.”

The last time a team started three different goalies in a playoff series and won it was a Laviolette-coached Philadelphia team in 2011.

The Capitals also saw the return of Evgeny Kuznetsov to the lineup after he had been placed on the covid-19 list at the same time as Samsonov. Kuznetsov skated on the top line with Ovechkin and T.J. Oshie. Oshie missed the team’s morning skate Wednesday for undisclosed reasons, but he slotted in with no apparent minute restrictions.

Eller’s absence created ripple effects throughout the lineup. Michael Raffl was shifted to third-line center, and Daniel Carr was inserted into the lineup over Daniel Sprong. Carr, who played in six games during the regular season, got 10:33 of ice time in his NHL postseason debut.

“I’m not going to sit here and say that we’re happy,” Capitals forward Tom Wilson said. “It’s a playoff game, and we didn’t get the result we wanted.”