Danny Espinosa's RBI single in the seventh inning turned out to be the difference as the Nationals clipped the Cardinals, 4-3.  Daniel Descalso clubbed a two-run dinger and Tony Cruz added an RBI double for the Cards, who have dropped five-of-six.  Lance Lynn was saddled with the loss.  The Cardinals start a six-game homestand today with the first of three against the New York Mets.  First pitch is at 1:15 p.m.