The surprise challenge was created and accepted on April 5, said Brian Dumoulin.

The Pittsburgh Penguins learned defenseman Kris Letang would be lost for 4 to 6 months because of surgery to repair a herniated disc in his neck.

Outside the Penguins’ dressing room, questions lingered whether this group could win the Stanley Cup without Letang.

Inside, the feeling was different.

“Yeah, we did” think we could do it, said Dumoulin, the Biddeford native who has stepped up as a key defenseman for the Penguins, now two wins away from winning back-to-back Stanley Cups. The Penguins lead the Predators 2-0 in the series, which heads to Nashville for Game 3 on Saturday night.

Pittsburgh has gotten this far with a mostly unheralded collection of defensemen. It hasn’t always been pretty – they’ve needed a good amount of help from the talented forwards, and goaltenders Matt Murray and Marc-Andre Fleury – but they’ve done the job well enough to keep moving on.

“We know no one’s going to replace (Letang),” said Dumoulin. “We know that, and we’ve just got to continue to play well as a group and don’t get outside of (your) comfort zone. Everyone just do what they do best.”

Dumoulin’s stats don’t tell the full story – one goal and 14 assists in 70 regular-season games, plus one goal and three assists in 14 playoff games.

In Game 2 on Wednesday, Dumoulin tied Phil Kessel for the team high in shots with four. He was also plus-2, being on the ice for two Pittsburgh goals and none against.

Despite plenty of injuries for the Penguins – in addition to Letang, Pittsburgh played without Olli Maatta and Trevor Daley for much of the stretch run, and Justin Schultz and Chad Ruhwedel during the Eastern Conference finals against Ottawa – here they are.

“We have a group back there that cares about each other,” said assistant coach Jacques Martin, who oversees the defense.

“They’ve been able to raise their level of play.”

The Penguins had to endure long stretches against Ottawa with five defensemen after losing Schultz to an upper-body injury in Game 2 and Ruhwedel to a concussion in Game 4.

Accustomed to juggling five – instead of six – healthy bodies for much of this season, Martin and his charges simply dug deeper.

“I have tremendous respect for our five guys who have played extra minutes and play in different positions,” Martin said. “We were able to win both of those games.”

Letang, 30, did it all for the Penguins during their run to the Stanley Cup last season. A case could have been made for him to win the Conn Smythe Trophy instead of Sidney Crosby, even before he scored what proved to be the Cup-winning goal in a 3-1 victory in Game 6 against the San Jose Sharks.

“Without Kris Letang, other people have filled in and have given us good minutes,” Martin said.

And it’s been a group effort. More than once, Pittsburgh has been forced to go long stretches in games with only five defensemen. When Schultz left Game 2 against the Senators, Dumoulin played 26 minutes, Ron Hainsey nearly 25 and Maatta 22. The Penguins won 1-0 to even the series.

“If you look at last year in the playoffs, it was Kris Letang and then the rest of us,” Dumoulin said. “That’s not the case right now. Obviously, whatever role that you’re asked to do, whatever opportunity is there, you’re going to do it. We’re not going to be the offensive guy Kris Letang was. Nobody is going to be in that aspect.”

The Predators have four impressive defensemen who would qualify as a No. 1 on some teams with Roman Josi, P.K. Subban, Mattias Ekholm and Ryan Ellis, but Dumoulin said focusing on his own job is more important.

“That’s fine with us,” Dumoulin said. “Obviously, they’re great players, but there’s no chip (on) our shoulders. We don’t really pay attention too much. We try to stay level-headed as much as we can. We know what we are as a (defensive) corps. There’s definitely a lot of talk, but we just take the same approach that we have been and go from there.”