In nearly 11 years of baseball back in the District, the Nationals have barely played any regular-season games of truly significant magnitude. Think about it: They ran away with the NL East title in both 2012 and 2014. They collapsed in 2005 before hitting the stretch run. They waited too long to go on their run in 2013.
Really, the only game in the last decade that comes to mind as a must-win game against another club in the race for the division came on July 21, 2012. The Nats had blown a 9-run lead to the Braves the night before, then lost the opener of a doubleheader, 4-0.