Zimmerman crushed an 0-1 pitch over the wall in center field for his second homer of the night and 16th of the season to cap a dramatic game on a blistering night at Nationals Park.
The first-pitch temperature was 99 degrees, the hottest for a home contest in Nationals history.
There was also a spectacular play on the defensive side for the Nationals in the ninth inning. Scott Hairston doubled to left field corner and his brother, Jerry Hairston Jr., tried to score from first base. Shortstop Ian Desmond took Josh Willingham's throw and made a perfect relay strike to catcher Ivan Rodriguez, who applied the tag for the final out of the frame.