Nationals vs. Giants: Washington scores two runs in ninth to finish sweep The slog of a baseball season, even for the best teams, presents countless invitations to just forget it, to slack, to conserve for another day. Thursday night, the Washington Nationals trailed by four runs in the seventh inning. They had already won their series against San Francisco. The pitcher who might start the All-Star Game opposed them. It seemed like a good time to start thinking about tomorrow. But 19-year-olds tend only to think about today. Ian Desmond smashed a home run, a glimmer that Bryce Harper stretched into certainty. In the dugout, as Desmond circled the bases, Harper turned to Adam LaRoche. "We're going to win this game," Harper told him. Just be ready for it. In the ninth inning, they were ready. Harper singled home the tying run, and then LaRoche scored him with a bases-loaded grounder to lift the Nationals to a 6-5 victory, their league-leading seventh walk-off win this season. When Brandon Belt could not scoop Brandon Crawford's throw in the dirt to convert a double play, it eliminated extra innings and sent the Nationals to their fourth straight victory and a sweep of the team that entered this series with the second-best record in the National League. With the woeful Colorado Rockies coming into town, the Nationals have built their winning streak with consecutive victories over Tim Hudson, Tim Lincecum, Madison Bumgarner and, Thursday night, Matt Cain. The Giants entered the series with a remarkable 74-1 record in the past 75 games in which they lead by at least three runs. On consecutive days, the Nationals have erased such a margin en route to two victories. "We're getting that sense that we're never out of it," LaRoche said. Somebody new is going to come through every night. The Nationals and Giants wore throwback uniforms as a turn-back-the-clock tribute to the 1924 World Series, and the Nationals, 88 years later, again have the best record in their league. They have won seven of nine, and their latest victory nudged them to a season-high 16 games over .500. The surge has bumped their winning percentage to an even .600, another clue that points to the likelihood of meaningful October baseball in Washington for the first time since 1933. In the past 10 seasons, 37 teams finished July 5 with a .595 winning percentage or better. Thirty-four of them would have made the postseason under the current playoff design, which for the first time includes a second wild card winner. The 2005 Nationals, 51-32, were one of the three teams that would have tumbled out of the playoffs even under the new format. Those Nationals had scored the same number of runs as their opponents, a dooming predictive measure. These Nationals have outscored opponents by 60 runs. "They had the front end of their rotation and we had the back end of ours, and we swept them," said closer Tyler Clippard, who earned the win with a perfect ninth. I doubt that there was too many doubts about what kind of club we had at this point in the season. But they know now not to doubt us.