Washington, DC (SportsNetwork.com) - Alfredo Simon turned in seven outstanding innings in another victorious effort on the road, leading the Cincinnati Reds to a 2-1 win over the Washington Nationals in the rubber match of a three-game set.

Simon (6-2) permitted just one run on five hits and a walk to improve to 5-0 in five starts away from home this season, with the effort giving the Reds their first series win in Washington since June 4-6, 2010.

The Nationals' lone score came on a leadoff home run from Denard Span in the bottom of the first.

"Anytime you lead off the game with a home run, you usually think it's probably going to be a good day for the offense," said Span. "But you've got to give credit to Simon. He shut the door down, made good pitches."

Zack Cozart aided Simon's cause by going 3-for-5 with a run scored, while Brandon Phillips and Brayan Pena delivered RBI singles for Cincinnati.

Washington starter Tanner Roark (3-2) pitched well in a losing cause, allowing two runs -- one earned -- over six innings of work.

Simon served up Span's blast into the bullpen in right on his second pitch of the afternoon, but was nearly spotless after working out of a second-inning jam and departed with a lead thanks to a two-run Cincinnati fourth.

Cozart opened the inning with a double -- the Reds' first hit off Roark -- and raced home on Phillips' single up the middle to knot the score at 1-1. After a throwing error by Washington third baseman Kevin Frandsen on a force play kept Phillips on the basepaths, Pena drove him in with a go-ahead single to left.

Washington had a chance to pad their early advantage when two singles and a walk loaded the bases with one out in the second, but Simon got Roark to ground into a double play.

The Nationals generated few scoring chances the rest of the way, with Simon returning from a 61-minute rain delay in the top of the sixth to set down 6- of-7 hitters when play resumed.

"I'm happy with myself right now," Simon said. "I know the bullpen was [tired] right now. I just tried to go out and throw seven or eight innings."

Washington did threaten against Jonathan Broxton in the eighth. Span led off with a single that was successfully challenged by Nationals manager Matt Williams after being ruled a catch by Reds center fielder Billy Hamilton, then was on third with two outs following a sac bunt and a flyout.

Broxton fanned Wilson Ramos to end the inning, however, and Aroldis Chapman fanned two during a perfect ninth to close out the triumph.