NEW YORK — As Brad Marchand carried the puck over the offensive blue line on Thursday, Nick Leddy tried to close on the left wing.  

Leddy is the Islanders’ best defenseman. Four seasons have passed since Leddy was teammates with Duncan Keith. But the ex-Blackhawk still plays as if Keith is offering him on-ice wisdom to defend with his feet and stick. 

Marchand made Leddy look silly. 

As the defenseman leaned toward the puck, Marchand twirled off Leddy to escape from his check. Leddy had no choice but to trip Marchand for a delayed penalty. Even from his stomach, Marchand did not quit on the play. He knew a friend was coming. 

Patrice Bergeron watched the sequence unfold. By the time Marchand was tumbling to the ice, Bergeron kicked it into a higher gear to make himself available in the high slot. A down-and-out Marchand slid a backhand dish to Bergeron. The center fought off Tanner Fritz’s check, spun, and whipped his third and final goal of Thursday’s 5-2 win past Jaroslav Halak at 3:45 of the third period.

 “The way Marshy and Bergy have developed chemistry over the years, it’s special to watch,’’ Torey Krug said. “They know where each other are on the ice the whole game. You just want to take a second to make sure you take it in sometimes.’’

Henrik and Daniel Sedin share a telepathic gift. Other tandems may not share genes, but they have mimicked the twins’ talent of anticipating each other’s moves: Nicklas Backstrom and Alex Ovechkin, Ryan Getzlaf and Corey Perry, Steven Stamkos and Nikita Kucherov, Tyler Seguin and Jamie Benn.

But there is no up-front combination that plays with the all-around lethality, efficiency, and doggedness of Bergeron and Marchand. One is the reserved center. The other is the gregarious left wing. Somehow, these two mismatched puzzle pieces click into place perfectly to form a dream tandem. 

Since 2010-11, Bergeron and Marchand have mostly played together in every situation. They run riot over opponents at even strength. On the penalty kill, their tenaciousness on the puck turns defensive stands into chances off the rush, usually for Marchand. 

 In retrospect, it is amazing and alarming Marchand was not always a full-timer on the No. 1 power-play unit. But as they do in every other quadrant of the rink, Marchand and Bergeron make sweet music while playing their respective positions of right-side goal-line man and net-front bumper. 

 Perhaps the only time they will be apart will be at the All-Star Game in Tampa. Marchand is going. Bergeron is not, a casualty of the NHL’s rule that every team must be represented. Otherwise, Auston Matthews would probably not have gotten the nod over Bergeron.

 “He deserves to be there. There’s no question,’’ Marchand said. “He’s easily one of the best players in the league. He’s very consistent every night, every year. He definitely deserves to be there. But anytime you get a break, it’s nice to get a little breather and spend time with the family. It’s enjoyable. We’ll all get back to work after.’’

Bergeron’s hat trick Thursday:

 As deserving as Bergeron is to be in Tampa, he would not want to represent the Bruins at the cost of his wingman. Bergeron has company among the NHL’s elite 200-foot centers. Anze Kopitar is his closest peer. In comparison, no other left wings come close to Marchand’s three-zone excellence — not Benn, Taylor Hall, or Claude Giroux. 

Marchand has willed himself to excel in all areas of the game. Because of his strength and creativity, he can grind and create down low in rope-pulling situations. When he’s stationary, Marchand’s strength on his skates and refusal to cede territory make him difficult to dislodge from dangerous areas. 

But the defining characteristics of his game are speed and relentless puck pursuit. These qualities turn Marchand into a rush threat at all times. When he’s at full tilt, Marchand has a deep bag of tricks. He can slam on the brakes to look for a teammate, circle back and reset his trajectory, snap off pucks in mid-stride, or continue attacking the net at his frenzied pace.

 “He’s unpredictable, for one,’’ said coach Bruce Cassidy. “He can go forehand, backhand. He’ll shoot. He’ll turn up. He’ll attack. He’s just so strong on his feet. And he never quits. It’s usually second or third effort. You saw that [Wednesday] night against Montreal on the play he made at home. The other thing he does well that’s very deceptive is he whacks the other guy’s stick. He almost puts the puck out there, baits him, and whacks the stick out of the way. So there’s an IQ level there as well. Only he knows it when he’s doing it. But it’s a very effective play for him. I just think it’s his dog-on-the-bone mentality and his strength on his feet.’’

When he’s flying, Marchand has the skill to be a solo offensive initiator. But what adds another layer of danger to Marchand’s full-speed game is Bergeron’s awareness of complementing his turbocharged left wing. Bergeron is not as fast as Marchand. But he knows how, when, and where to get open for his linemate.

Marchand and Bergeron support each other all over the ice. It’s why they are the best tandem in the league.

Fluto Shinzawa can be reached at fshinzawa@globe.com. Follow him on Twitter @GlobeFluto.