The thing about pinch hitting is, it only takes one swing. One minute, Chad Tracy can be sitting in the Washington Nationals dugout, a bystander as victory nears. The next, he may be running to the end of the tunnel for two emergency warmup hacks. One night, he may be staying up in bed wondering when the next hit will come. The next, he could pump his fist while circling the bases, having rescued the other 24 men in his clubhouse from an agonizing loss. Tracy and the core of Nationals pinch hitters he leads – the Goon Squad, they call themselves – had flailed through the early season. In the 10th inning Friday night, Tracy blasted Huston Street’s elevated change-up over the right-field fence at Petco Park, lifting the Nationals to a harrowing, 6-5 victory over the San Diego Padres. With one swing, Tracy struck a blow for Washington’s bench, bailed out Ryan Zimmerman after another throwing error and made the Nationals, in their 42nd game, the final National League team to record a pinch-hit RBI. “As a collective group, we haven’t really come in and won a ballgame for us yet,” Tracy said. “Last year, we did that early on in the first series of the year. It took a little longer this year. That’s something that can get us going. We can feed off each other.” Even after Tracy’s home run, the drama persisted. With Rafael Soriano having blown a save in the ninth, Drew Storen pitched a heart-stopping 10th for his first save of the season. He wiggled out a first-and-third, one-out jam only after a strikeout and a nearly disastrous bobble by Zimmerman. “That one gave me a few more gray hairs,” Manager Davey Johnson said. “And I don’t need any more.” It should have been an easy night. Adam LaRoche clobbered two homers and drove in four runs, continuing to drag the Nationals’ scuffling offense to respectability. Zimmerman added one of his own, giving the Nationals a 5-2 lead after 51 / 2 innings. Starter Gio Gonzalez handed a 5-3 lead to Tyler Clippard with two outs in the sixth, and Clippard carried the ball into the ninth, to Soriano, who had been automatic. Tracy, out of habit, noticed Soriano’s spot in the order was due up third in the top of the 10th. With one out in the ninth, protecting a 5-3 lead, Soriano induced a chopper from Chris Denorfia. The ball bounced to the left side of the infield, one of the final pieces to a victory for the Nationals. Zimmerman and shortstop Ian Desmond had consulted before the play and decided that Desmond, with Soriano throwing cutters to a right-hander, would play up the middle.