Marco Sturm is pushing all the right buttons for the Bruins

There's an old adage in hockey that you don't change a winning lineup. Marco Sturm, whose Bruins have now won five straight after Saturday's 4-1 win over the Kings, was forced to make one Saturday due to an upper-body injury that sidelined Pavel Zacha for at least one game.

Sturm opted to make a second change, and it was a bold one: healthy-scratching Nikita Zadorov after the veteran defenseman took three penalties in Friday's 4-2 win over Anaheim, including an ill-advised double-minor in a one-goal game.

If the Bruins had lost Saturday, and maybe looked like a team that could've used a physical presence, Sturm's decision would've been second-guessed. In the first period, it actually did look a little bit like that. The Bruins got off to another poor start and trailed 1-0 after one.

Sturm's new lines with Zacha out weren't doing a whole lot, especially the new first line with Fraser Minten centering David Pastrnak and Morgan Geekie. That trio spent pretty much all of their first-period shifts in the defensive zone chasing around Los Angeles' top line.

Pastrnak caught a break early in the second period and took advantage, though. After a puck skipped past Kings defenseman Erik Gustafsson, Pastrnak pounced on it and raced the other way before firing a shot stick-side past Anton Forsberg.

Sturm still wasn't thrilled with his team's offense after two periods, though, so he changed things up again. He moved JJ Peterka up to the top line and dropped Geekie to the new-look second line with Matt Poitras and Marat Khusnutdinov.

After Geekie-Minten-Pastrnak had gotten out-attempted 17-4 during their 5-on-5 shifts, Peterka-Minten-Pastrnak completely flipped that and out-attempted the Kings 11-5 in the third period. They got their reward late when Peterka scored an empty-netter to push Boston's lead to 4-1, with the assists going to Pastrnak and Minten.

The other empty-net goal right before that was scored by Elias Lindholm, who now has five points in five games since being dropped to the third line -- another right button pushed by Sturm.

The new second line, meanwhile, scored the biggest goal of the night with 6:24 left in the game, the one that proved to be the game-winner. Jonathan Aspirot, the defenseman Sturm put in for Zadorov, started the sequence with a crisp breakout pass to Geekie. Geekie sent Poitras into the offensive zone, Poitras dropped a pass back to Geekie, and Geekie fired a shot that handcuffed Forsberg. Poitras drove right to the net and poked the rebound over to Khusnutdinov for a tap-in.

Sturm's show of faith in Poitras continues to pay off. The 22-year-old center had supplanted veteran Sean Kuraly at fourth-line center and produced in that role, with four points in five games. Now with Zacha out, Sturm moved him up a couple lines, and Poitras continued to produce at a critical moment.

The investment in youth extends to the likes of Minten, Khusnutdinov, James Hagens and Frederic Brunet, too. Minten and Khusnutdinov have both moved up the depth chart since starting the season on the third line. Minten, in particular, now has eight points in nine games, tied with Geekie for second on the team. Hagens has six points, tied for the league lead among rookies. Brunet scored his first NHL goal on Friday and continues to just play a really solid all-around game.

The Bruins have now outscored opponents 16-5 in the third period on the season, which is the best third-period goal differential in the NHL. Sturm's in-game adjustments, like the ones he made Saturday, deserve at least some of the credit for that.

"We're seeing a team that never gives up," Sturm told NESN after the game. "It doesn't matter how bad we start sometimes, and if we're behind a goal or two, we just keep playing our game. I think each period, we're just getting better and better. Goaltending again was a big key to our success, but it's just another great team effort. That's the Boston Bruins right there."

As Sturm referenced, Jeremy Swayman was great again in net. He stopped 25 of the 26 shots he faced and is now 6-1-0 on the season, tied with former tandem-mate Linus Ullmark for the league lead in wins.

And because the Bruins won, Sturm also deserves credit for sitting Zadorov down for a game. Zadorov's undisciplined play did need addressing. Sturm didn't necessarily need to scratch Zadorov to send that message, but doing so can serve as a wakeup call to other veterans that their spots in the lineup aren't safe if they fail to meet the standard that's expected of them.