After reliever Eric O'Flaherty (1-1) walked Adam Kennedy leading off the ninth, Peter Moylan came in and gave up a double to Ryan Zimmerman, then intentionally walked Cristian Guzman to load the bases with no outs. Harris then grounded a single past diving second baseman Martin Prado.
The Nationals raced from their dugout to celebrate on the field, mobbing Harris near first base.
Tyler Clippard (4-0) got the final five outs after Olsen departed. The starter allowed only two hits, none until David Ross' clean single to left with one out in the eighth.
http://accesswdun.com/article/2010/5/229218