Washington (6-14) at Philadelphia (8-11)

The Philadelphia Phillies and Washington Nationals may be the bottom two teams in the NL East, but they’re heading in different directions.

The Phillies go for their fifth straight victory when they continue a three-game series with the slumping Nationals on Wednesday at Citizens Bank Park.

Philadelphia (8-11) began the season a dismal 4-11, but has won its last four contests to move 2 1/2 games ahead of the last-place Nationals. The Phillies are outscoring opponents 30-11 during their winning streak, batting .326 while the pitching staff has posted a 2.75 ERA.

They used a three-run eighth inning to beat Washington 6-3 in Tuesday’s series opener, handing the Nationals (6-14) their third straight loss. Wes Helms drove in the go-ahead run with a single in that decisive frame, and has hit safely in all but three of the 17 games he’s appeared in this season.

Aaron Rowand went 2-for-4 with a homer and two RBIs to extend his hitting streak to 12 games, batting .435 with five doubles, three homers and eight RBIs in that span. The Phillies center fielder is also hitting .385 in 78 career at-bats versus the Nationals, including 12-for-26 in his last six games against them.

The production of Helms and Rowand has helped offset the struggles of All-Star second baseman Chase Utley (.250 batting average) and reigning NL MVP Ryan Howard (.207).

“That’s what we have to do when our big guys aren’t hitting,” Helms said. “That’s what this lineup can do.”

Jon Lieber (0-0, 3.38 ERA) makes his second start of the season for Philadelphia on Wednesday. The right-hander replaced Brett Myers in the rotation last week and was dominant in his first start.

He pitched 5 2-3 shutout innings on Friday, allowing just one hit and one walk while striking out five, but didn’t record a decision in the 2-1, 10-inning defeat to Cincinnati. Lieber, who has also made two relief appearances this season, is 9-8 with a 4.05 ERA in 24 career games versus Washington, including 21 starts.

He will be opposed by John Patterson (0-3, 7.00), who has struggled in 2007, after undergoing right forearm surgery last year that ended his season in July. The right-hander’s last start also came against Philadelphia on Thursday, when he allowed three runs, seven hits and four walks over four-plus innings of a 4-2 defeat.

Patterson, who fell to 1-3 with a 4.37 ERA in six career starts versus the Phillies, said his right arm felt tight, causing him to lose as much as 10 mph off his fastball.

“It’s not even close,” said Patterson, who has not recorded a win in more than a year. “I’m having to swallow a lot of pride right now.”

The Nationals have been outscored 27-12 during their three-game skid, batting just .216 while the pitchers have compiled an 8.25 ERA.

“Baseball is like boxing. If you don’t hit, the other guy is going to hit you back,” Nationals manager Manny Acta said.

Washington center fielder Ryan Church was 2-for-4 with an RBI double Tuesday and is 3-for-5 with two homers during his career versus Lieber.