Before the playoffs began, questions were raised about whether this edition of the Rangers — a swift, north-south team — was really built for the playoff grind against teams with more size and muscle.

The first answer came in the opening round, when the Blueshirts found a balance between the grind and the glory and knocked off the Montreal Canadiens, closing out the series with a 3-1 victory in Game 6 at Madison Square Garden on Saturday night.

In fact, Mats Zuccarello, the smallest player on the ice at 5-7, came up huge and the resilient Rangers, who had trailed two games to one in the series, are going to the second round of the Stanley Cup playoffs.

“I think we answered those questions,” Marc Staal said. “I thought everyone stepped up, played hard, finished checks, took hits to make plays, all those things you need to win a series.”

Zuccarello, who led the team with 59 points during the regular season, scored twice in the second period — once on the struggling power play — to rally the Rangers from a 1-0 deficit.

“It’s incredible the impact he has on this team,” captain Ryan McDonagh said. “You guys see it on the ice, but in the locker room, he’s a big-time mentor for a lot of our young forwards. The way he plays, he backs down from no one. It’s great to see him rewarded here. He’s taken abuse and never once complained about it, just fought through it his whole time here in New York.

“He’s got a nose for where the puck’s going to be. We know about his playmaking ability and sometimes I tell him he’s got to trust his shot.”

Zuccarello had that trust Saturday night during the third straight win for the Blueshirts, who next will face the Ottawa Senators or the Boston Bruins. The Senators lead that series 3-2, with Game 6 today in Boston.

Even with Zuccarello’s heroics, the Rangers still had to protect the lead in the third period. Chris Kreider’s high-sticking penalty at 9:07 raised the tension level in the stands, but the Rangers and Henrik Lundqvist, who was sharp and had 27 saves, silenced that threat.

Lundqvist kicked out Tomas Plekanec’s close-in shot with his left pad with 1:30 left, and Carey Price was pulled for an extra attacker with 1:17 remaining. Derek Stepan’s lofted 180-foot shot into an empty net sealed it.

“We needed our best effort tonight and we got it,” Lundqvist said. “All 20 guys worked extremely hard. We had jump from the get-go. We created more chances. Montreal had some chances in the first, but after that, we controlled the game . . . I think the patience we showed and the confidence in this situation was great to see.”

Zuccarello, whose three goals were the most of any player in the series, skated on a line with Kevin Hayes and J.T. Miller, who played their best game of the series as well.

After defenseman Jordie Benn pulled down Pavel Buchnevich to give the Rangers their first power play at 1:30 of the second period, Zuccarello snapped the Blueshirts’ 0-for-14 skid with his second goal of the game. Mika Zibanejad’s cross-ice pass found Zuccarello, and with Price sliding to the opposite post, the winger’s shot from the right circle eluded him at 2:26.

The goal enlivened the Rangers, who were outplaying the Canadiens in the second period and outshooting them 10-4 when, after a terrific cycle in the Habs’ zone, Hayes spun near the left circle and sent a pass to Zuccarello in front that he buried at 13:31 for the 2-1 lead.

Players predicted that the Canadiens would come out of the gate hard, and in the first period, they indeed showed the desperation.

When Lundqvist gloved a soft dump-in at 4:51, Alexander Radulov braked at the crease and gave him a snow shower. McDonagh immediately took exception, shoving him away. The officials kept them apart, but at the blue line, Max Pacioretty had cross-checked Jimmy Vesey, and the two had a short bout.

The forechecking Canadiens continued to dump pucks into corners and retrieve them, and Alexei Emelin’s wrister from the left circle went through traffic in front and sailed over Lundqvist’s glove for a 1-0 lead at 6:19.

After that, it was all Rangers.

“It’s going to be nice to have a couple days off,” Zuccarello said, “but it’s only the first round.”