This is how they do it, because this is how they always do it. It might not be a widely known fact, but the Devils are again showing themselves to be one of the best teams in hockey, another notch in their whipping pole coming yesterday afternoon when they beat the formerly first-place Penguins, 3-1, at a soldout Prudential Center. “We’re going through a really tough part of the schedule here,” coach Pete DeBoer said of his 7-1-3 club, now winners of four straight and usurpers of the conference lead. “It’s a grind every day, but we really like how we’re approaching our preparation and keeping our composure and resiliency.” The only time the Devils have lost in regulation this season was last Saturday in Pittsburgh, when the Penguins (8-4-0) took it to them in a 5-1 win. The two teams immediately boarded flights yesterday and headed back to western Pennsylvania to do it again tonight, a playoff atmosphere created not just from the condensed schedule and the crucial divisional points, but because of the physical intensity inherent in two teams this good meeting this often. “We know it’s going to be a battle again,” said second-year center Adam Henrique, who scored the game-winner on the power play 10:56 into the third period. “We got a confident group in here right now and we have to keep that going.”