Penguins forwards Conor Sheary, Bryan Rust, Nick Bonino and Phil Kessel each has played an obvious role in building that lead in the best-of-7 series, but the root of Pittsburgh's play through two games has been much less obvious.

PITTSBURGH -- The Pittsburgh Penguins' unsung heroes have helped them build a 2-0 lead in the Stanley Cup Final against the San Jose Sharks.

It hasn't been flashy, but Pittsburgh's defensive effort has stifled San Jose's attack. Penguins coach Mike Sullivan hopes that continues in Game 3 at SAP Center in San Jose on Saturday (8 p.m. ET; NBCSN, CBC, TVA Sports).

"[The defensemen] really have been our unsung heroes," Sullivan said Thursday. "They go back for pucks, they make plays, they help us get out of our end zone, they're defending extremely hard and they're blocking shots. I think they're doing a lot of those thankless jobs that don't necessarily show up on a score sheet.

"They're difficult to quantify in a statistic, but they just help teams to win, and I know our team recognizes the contribution that our defensemen are making right now to this group and, as their coaching staff, we're certainly appreciative of their effort."

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Stats won't accurately indicate how well defenseman Olli Maatta has rebounded. With Trevor Daley out for the remainder of the Stanley Cup Playoffs with a broken ankle, Pittsburgh turned to Maatta in Game 5 of the Eastern Conference Final against the Tampa Bay Lightning.

Maatta had been a healthy scratch in the previous three games after noticeably laboring coming off one injury at the end of the regular season and another sustained against the Washington Capitals in Game 2 of the Eastern Conference Second Round on April 30. Since returning to the lineup May 22, Maatta seems to have caught a second wind next to defenseman Ben Lovejoy.

With decreased minutes on his current pair, compared to those expected of him as defenseman Kris Letang's partner, Maatta quietly has regained his form and assisted on three goals in five games.

Defensemen Brian Dumoulin, Ian Cole and Justin Schultz each has welcomed a larger role in Daley's absence, and that's impressed Sullivan.

"I really like the way our team's played," Sullivan said. "I think when we have had defensive-zone time, I think we've defended extremely hard, defended extremely well as a group cooperatively and so, that's my main goal here, is to make sure we get through those momentum swings without getting hurt, and I think our guys have done a real good job in that regard."

That effort isn't limited to the defensemen.

Bonino was lauded after scoring the game-winning goal in Game 1 (3-2), but his contributions aren't limited to that play. He missed two practices after blocking a shot by Lightning forward Jonathan Drouin in Game 7 of the conference final and has since blocked 10 shots in two games against the Sharks.

Rookie goalie Matt Murray made 21 saves in Game 2 and credited those in front of him.

"They've been great," Murray said after the game Wednesday. That's a huge thing in being successful, I think, in the postseason is blocking shots, especially against this team, where they try to throw pucks from the point. … So, [Bonino] was great once again. He's always blocking a lot."

That's a big reason the Sharks are averaging 24 shots on goal through two games, after averaging 28 in the playoffs before starting the Cup Final. At one point in the second period Wednesday, San Jose went 11:06 without a shot.

"I think we have a brave group," Sullivan said. "We're willing to block shots. We're getting into the shot lanes. We're boxing out trying to get sticks in front to make Matt's job as easy as possible, as far as his sightlines and his movement. So it's really been an impressive effort from our team so far.

"We're going to need more of it moving forward. We have a lot of work to do ahead of us, and we're well aware of that. And we're just going to have to continue in that same vein."