Monday night seemed close to perfect for the Washington Nationals, until it veered close to catastrophe. A blistering afternoon yielded to a warm Southern California night, Jordan Zimmermann further asserted himself as one of baseball’s elite starting pitchers, Ryan Zimmerman stayed hot and first place beckoned. And then Bryce Harper was there on the Dodgers Stadium warning track, lying still on his back as trainers rushed toward him and the ballpark hushed. The Nationals thumped the Los Angeles Dodgers, 6-2, and survived a mighty scare. Harper walked off on his own power in the fifth inning after a frightening, face-first collision with the right field fence that left him bloodied and the rest of the Nationals startled. Harper received 11 stitches under his chin but did not suffer a concussion, according to Nationals officials and Harper’s agent Scott Boras. Harper also underwent “precautionary” X-rays on his jammed left shoulder, Manager Davey Johnson said. He also bruised his neck and knee. The prevailing sentiment was that Harper would probably miss a game or two — even if he pleaded to stay in Monday night as blood dripped down his neck. “Bryce is going to be all right,” Johnson said. Harper’s nasty crash into the outfield wall prevented the Nationals from fully celebrating the latest gem from Zimmermann, who is making a routine out of mastery. He allowed two runs over 72 / 3 innings, striking out five Dodgers and scattering nine hits as he became the first pitcher in the majors to reach seven wins. Zimmermann carved through the Dodgers’ lineup, daring them to hit his 95-mph fastballs, mixing in just enough biting sliders, always coming straight at them. Paced by Zimmerman’s two-run, bases-loaded double, Zimmermann settled his ERA at 1.69. Since the start of the 2012 season, the only pitchers with an ERA better than his 2.65 are Clayton Kershaw (2.35) and Justin Verlander (2.52).