WASHINGTON — Heavily favored to beat the young and inexperienced Toronto Maple Leafs, the Stanley Cup-contending Washington Capitals weren’t supposed to be the team that flubbed and floundered at the start of the playoffs.

Playing some of their worst hockey of the season, the Capitals fell behind by two goals early but came back to force overtime. Tom Wilson scored 5:15 into extra period for a 3-2 victory in Game 1 on Thursday night.

“It’s hard to say what was up there,” captain Alex Ovechkin said. “Maybe we was a little bit nervous, maybe kind of feel the pressure a little bit. But when they score, all the bench said, ‘Just calm down and let’s play our way.’ Coming back in after first there was no panic, obviously still lots of minutes to play. ... We just grinded it out and win in overtime.”

Playoff star and 2014 Conn Smythe Trophy winner Justin Williams scored twice in regulation and Braden Holtby stopped 35 of the 37 shots he faced to give Wilson the opportunity to be the hero. The fourth-line winger who grew up a Maple Leafs fan in Toronto beat Frederik Andersen to the far side for his first NHL playoff goal.

Williams said to Wilson afterward, “It feels good, doesn’t it?” The Presidents’ Trophy-winning Capitals could exhale because they survived a serious scare from the Maple Leafs in their playoff opener.

Despite having nine players making their playoff debuts, Toronto showed no fear of Washington, as rookie Mitch Marner scored 1:35 in and Jake Gardiner made it 2-0 at the 9:44 mark. Andersen made 41 saves but lost track of the puck in front of him on Williams’ second goal and should have stopped Wilson’s shot.

“I thought Freddie was really good, and then he’d probably like to have that back,” coach Mike Babcock said. “But he gave us an opportunity, so I don’t think you can argue with that.”

Williams gave the Capitals the opportunity to bounce back from their rough start with the fourth two-goal game of his playoff career. Defenseman Kevin Shattenkirk, who led all players with nine shots on net, said the team rallied around Williams — the veteran who reassured everyone at intermission.

“In between periods it was basically Justin just kind of calmed everyone down, said, ‘Relax, we’re not going to win every period,”’ Holtby said. “That’s what leaders do. He got us a big couple goals and fought hard all game.”

Then Wilson prevented the Capitals from really feeling the pressure going into Game 2 Saturday by finally finding the net in his 29th playoff game. Growing up a fan of Maple Leafs players like Darcy Tucker, Ed Belfour, Curtis Joseph, Shayne Corson and Mats Sundin, he never envisioned scoring this kind of goal against his boyhood team.

“You’ve lived this moment in your brain when you’re a young kid in the backyard or whatever when you’re 8, 9, 10 years old,” Wilson said. “So let’s just go out there and play. The playoffs are the best time of year. The building was unbelievable, the fans are second to none here and, obviously, a pretty good feeling putting that in the net.”

Wilson’s goal came two days after Babcock said the fourth-line winger is “not as big of concern as a lot of people” on the Capitals. The 23-year-old agreed with Babcock and tried to brush that off.

“He’s got a point,” Wilson said. “There are other guys that they have to worry about.”

Predators 1, Blackhawks 0

Pekka Rinne made 29 saves, Viktor Arvidsson scored in the first period and Nashville beat Chicago in Game 1.

Rinne’s second career postseason shutout sent Nashville to just its second playoff win in Chicago in seven tries. The Predators did not have a 1-0 victory during the regular season.

Corey Crawford had 19 saves for Chicago.

“We’ve got to be more desperate, need more desperation around the net in that willingness to get there and fight through it and pay the price, whatever’s there,” coach Joel Quenneville said.

The Blackhawks, who won the Central Division with the most points in the Western Conference, are going for their fourth Stanley Cup championship in the last eight seasons. They eliminated Nashville during two of those title-winning runs, including in 2015 when the Predators blew leads of 3-0 in Game 1 and 3-1 in Game 6 of their first-round series.

Ducks 3, Flames 2

Jakob Silfverberg scored the tiebreaking power-play goal late in the second period, and captain Ryan Getzlaf had a goal and an assist to lead Anaheim in the series opener.

Rickard Rakell scored the tying goal after Calgary made a horrendous line change in the second period, and John Gibson made 30 saves for the Ducks.

Sean Monahan and Sam Bennett scored and Brian Elliott stopped 38 shots for the wild-card Flames. Calgary is winless in Anaheim since April 25, 2006, when the Flames won a playoff game in a series won by the Ducks.

The Ducks have won five straight Pacific Division titles, but their postseason failures in recent years led to coach Bruce Boudreau’s firing last spring and the return of Randy Carlyle, who led Anaheim to its only championship a decade ago.