After being swept by the woeful Reds (21-31) last Thursday, the Nats’ prospects against the non-woeful Cardinals (33-18) looked pretty bleak. Friday’s inevitable loss brought the team to .500, a low since late April, when the team record was just 11-11. Then Saturday’s “L” put them under the halfway mark for the first time since the Nats’ seventh game of the season, where they fell to division rival Atlanta. But then something happened: the Nats…