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It was a pitcher's duel in the third test of a four-game set between the Atlanta Braves and Washington Nationals. Who knows what to expect from the NL East foes Thursday night in the series finale?

Atlanta had won the first two installments of the series, including an 8-1 drubbing on Tuesday. But the Nationals took care of business with Wednesday's 2-0 victory behind eight strikeouts and eight shutout innings from Jordan Zimmermann. Zimmermann allowed only two hits and Rafael Soriano put the icing on the cake with a flawless ninth for his eighth save.

"First inning I didn't have my best stuff. The fastball I was getting inside a little bit. I had good off-speed stuff and kept throwing that, then the fastball came back a little later in the game," Zimmermann said.

Braves starter Paul Maholm surrendered a costly home run to Ian Desmond in the fourth inning and was strapped with the loss. Maholm went eight innings, gave up three hits and struck out four.

"Pauly has been pitching well for us all season," Braves left fielder Justin Upton said. "It stinks when he goes out and pitches so well and we couldn't push anything across."

Upton and Maholm had the hits for Atlanta, which dropped its fifth game in seven tries and had a nine-game winning streak against Washington come to an end. Atlanta still leads the NL East by 3 1/2 games ahead of the Nats.

The Braves will host the New York Mets for three games this weekend, but look to finish off Washington with Kris Medlen on the mound. Medlen ended the 2012 campaign on fire and it hasn't carried over as evidenced by a 1-3 record in five starts to go along with a 3.26 earned run average.

Medlen allowed a season-high five runs and 10 hits in 5 1/3 innings the last time out on Saturday in a 7-4 setback at Detroit. In his back-to-back losses, Medlen has given up 17 hits and eight runs. The right-hander has pitched against Washington 11 times (2 starts) in his career, going 2-1 with a 1.67 ERA over 27 innings.

Countering for the Nationals will be Dan Haren, who is coming off arguably his best start of the season. In Saturday's 6-3 win over Cincinnati, Haren limited the visiting Reds to a pair of runs in six innings and permitted six hits to improve to 2-3 in five starts and lower his ERA from 7.36 to 6.29.

Haren, a right-hander, ended a personal two-start slide and hopes to maintain his strong record against Atlanta. Haren has made six career starts in this series and owns a 4-2 mark. However, his ERA in that span in 6.17.

The Nationals are counting on young star outfielder Bryce Harper to be in Thursday's lineup. Harper left Wednesday's win after aggravating a shoulder bruise on a check swing leading off the sixth inning. Harper collided with an outfield wall on Tuesday and is day-to-day.

"Hopefully, I can come in tomorrow, feel like a million bucks and play," Harper said on the club's website. "If I can play tomorrow, I'm going to play. I can play with pain. I can tolerate pain. There's hopefully nothing that can keep me out of that lineup tomorrow."

Harper could be joined by teammate and third baseman Ryan Zimmerman on Friday. On the disabled list since April 21 with a strained left hamstring, Zimmerman has been doing rehab assignments in the minor leagues and is expected to join the club in Pittsburgh Friday night.

"It only took seven, eight days for it to get completely better," Zimmerman noted on the Nats' website. "But then obviously you have to get back in game shape and play a couple games and get ready, so thankfully everything kind of went as planned and nothing really came back up. It's good. Hammies, you never really know."

Washington had lost three in a row and seven of 10 games before the recent win and will play three games in the Steel City this weekend.