PITTSBURGH -- When Pittsburgh Penguins coach Mike Sullivan was asked a question about his second line prior to Game 3 of the Eastern Conference Second Round against the Washington Capitals, he was confused.
"Which line is the second line?" Sullivan said.
The reporter said he was talking about the line of center Nick Bonino, right wing Phil Kessel and left wing Carl Hagelin.
"Oh," Sullivan said, still looking somewhat confused.
Sullivan admitted he needed clarification because he doesn't look at the Penguins' lines as first, second and third. That, more than anything, is proof of what Bonino, Kessel and Hagelin have done to balance the power in Pittsburgh's forward lines.
There used to be no doubt Sidney Crosby centered the first line and Evgeni Malkin centered the second line. The depth chart isn't as clear now with the emergence of Bonino's line.
Bonino, Kessel and Hagelin combined for one goal in each of the first three games against the Capitals. They were held in check despite some quality chances, including a semi-breakaway for Hagelin, in Game 4 on Wednesday.
The Penguins lead the best-of-7 series 3-1. They can eliminate the Presidents' Trophy winning-Capitals in Game 5 at Verizon Center on Saturday (7:15 p.m. ET; NBC, CBC, TVA Sports).
Video: PIT@WSH, Gm2: Hagelin nets pretty one-timer for lead
"One of the things we like about the makeup of our forwards at this point is the balance we have," Sullivan said. "Each line has threats to score. When you get that it makes your team harder to play against. You don't have to rely on any one or two players on a given night to score. [Bonino's] line has been real good for us for a long time now."
That it has is a testament to Sullivan's flexibility and willingness to experiment by moving Kessel away from Crosby and Malkin.
Former Penguins coach Mike Johnston tried to use Kessel with both star centers through the first two months of the season, but Kessel didn't seem to fit.
Maybe it was because Kessel thrives when he plays with a center who allows him to have the puck, to dominate the puck, and Crosby and Malkin each are at their best when they do the same.
Or, there is the theory of Penguins general manager Jim Rutherford. He thought they "tried too hard instead of just letting things unfold for them."
Regardless, Sullivan had to get more out of Kessel.
He put Kessel with Bonino and Chris Kunitz for a game against the Columbus Blue Jackets on Dec. 21. Kessel scored two goals with Bonino getting assists on each in a 5-2 win, Sullivan's first as Penguins coach.
Bonino and Kessel played together for a few more games, with Scott Wilson on the left wing, but it didn't last. Sullivan went back to using Kessel with Malkin. Kessel struggled for a while, got a kickstart when Hagelin was acquired in a trade with the Anaheim Ducks on Jan. 18, but struggled again.
It wasn't until Malkin sustained an upper-body injury March 11 that Sullivan went back to using Bonino with Kessel and now Hagelin beginning against the New York Rangers on March 13. The line combined for 17 goals and 43 points in the final 15 games of the regular season. Pittsburgh went 13-2 in that stretch.
Video: PIT@WSH, Gm1: Bonino finishes Hagelin's feed for tie
The line has seven goals and 22 points in nine Stanley Cup Playoff games. The Penguins are 7-2 and one win away from the Eastern Conference Final.
"I think we try to push each other," Hagelin said. "We have a good mix on the line. [Bonino] is an extremely smart player, picking up passes in the middle and winning battles down low. We know Phil has a rip of a shot and is an extremely great skater, but he's also good with the puck at making plays. I'm just trying to be out there to find pucks, use my speed."
Kessel thriving with Bonino shouldn't be a surprise. He found success with Tyler Bozak when he played for the Toronto Maple Leafs. He's at his best playing with centers who get him the puck in space and allow him to go to work. That's what Bonino does.
"Obviously you always want the puck out there and you always want it in good situations," Kessel said. "I seem to be getting it in good situations."
He is because of Bonino's patience and Hagelin's speed, which force the defense to back off, giving Kessel more room.
"I think I like to just play a pretty responsible 200-foot game, allow them to blow the zone, use their speed, try to make a good play and get it out to them," Bonino said. "I like to think I can play with anyone just because I can try to do a little bit of everything and make it easy on them, but especially with those guys, with their skill and their speed, it helps me be able to pass them the puck and get them in positions to score."
They've scored enough to blur the depth chart in Pittsburgh and shed the labels of first line, second line and third line.
"Regardless of what line we talk about, what I really like about our group right now is our balance," Sullivan said.