Every sector of the Washington Nationals has operated at full blast for the past week, but as they throttled another overmatched opponent Friday night, they only needed one pitcher. Their relievers took shelter in the bullpen. Their offense erupted, but every run that came after the game’s second batter proved cosmetic. All the Nationals required was the slightly stocky, out-of-nowhere starter who leads them in ERA. One of the hottest teams in baseball didn’t need anything more than Tanner Roark. At the end eighth inning of the Nationals’ 6-0 demolition of the punchless San Diego Padres, Roark walked into the third base dugout and bumped fists with coaches and teammates. “Hell of a job,” defensive coordinator Mark Weidemaier told him. He could celebrate one of the best games he ever pitched, one of the most dominating starts in the Nationals’ brief history. Roark struck out 11, walked none and allowed three hits over eight scoreless innings. “He’s been pitching like that for us all year,” Manager Matt Williams said. “Just continues to pound the zone, all of his pitches. Pretty impressive.” The Padres have scored the fewest runs in the majors, and earlier this season Roark had fired a shutout against them at Nationals Park. But a favorable matchup made his dominance no less impressive. It could not diminish the fact that Roark, a late-blooming 27-year-old, provided more evidence his ascendance cannot be considered a fluke. As he led the Nationals to their sixth win in seven games, Roark lowered his ERA to 2.91. “Everything felt good coming out,” Roark said. “I wasn’t holding anything back. I’m not trying to make perfect pitches. I was just throwing it, letting it go. If the hitter sees the same arm action on my fastball, you get ’em. … I don’t try to strike guys out. I just try to make good, quality pitches. Strikeouts happen.” Saturday, Blake Treinen will complete one cycle through the Nationals’ rotation. The last four starters have struck out 31 batters and walked one. Those four starters have also been supported by 25 runs. In the entire major leagues, only the Oakland Athletics, San Francisco Giants and Toronto Blue Jays own a better run differential than the Nationals’ plus-33. The Nationals do not own the record of an elite contender, but they are trending in that direction. “You definitely feed off it, for sure,” Roark said. “The rotation is doing so well. The relievers are doing so well. The bats are coming alive. It just gives you that much more confidence. You know we’re going to score runs.”