Wade Miley aims for his 13th win of the season this evening when the Arizona Diamondbacks continue a three-game set with the Washington Nationals at Chase Field.

Miley pitched well enough to win his last time out, but lost for the second time in three starts, despite giving up just an unearned run and six hits in in six innings to the Pittsburgh Pirates.

"It was a tough loss," Arizona outfielder Chris Young said. "Wade pitched his butt off tonight and the offense wasn't able to score any runs."

Miley, who has allowed just one earned run over his last 14 innings, beat the Nationals the only other time he faced them and held them scoreless over six innings.

Washington will counter with righty Edwin Jackson, who is 6-7 with a 3.56 ERA. Jackson did not get a decision on Monday in Houston, as he allowed two runs and two hits in 5 1/3 innings. He also struck out eight in the 5-4 win.

"Edwin, I thought he had pretty good stuff," Nats manager Davey Johnson said. "But he was on pace for 120-something pitches if he goes six, and his misses were really bad misses."

Jackson is 1-2 lifetime versus the Diamondbacks with a 3.90 ERA in six games (5 starts).

Washington won its seventh straight game in Friday's opener, as Stephen Strasburg and three Nationals relievers combined on a three-hitter in a 9-1 win.

Strasburg (13-5) walked four in his outing, but only allowed one hit and one run over six frames to earn the victory. He struck out six. Sean Burnett and Ryan Mattheus each hurled a perfect inning in relief, while Craig Stammen gave up two hits in a scoreless ninth.

Ryan Zimmerman belted a two-run homer, Michael Morse added a solo shot and Steve Lombardozzi went 4-for-5 with four runs scored for NL East-leading Washington, which has won 17 of its last 21 games.

"I don't think any of us are satisfied, we still have our best baseball ahead of us," Strasburg said.

Trevor Cahill (9-10) was charged with four runs on six hits and three walks over six innings in defeat. Arizona was coming off a 6-4 road trip.

Washington took two of three from Arizona earlier in the year.