Philadelphia (75-63) at Washington (53-85)

It’s apparently going to take a strong effort to beat the Washington Nationals these days. A gem from Philadelphia Phillies ace Cole Hamels may not even be enough.

After slipping in the NL East race, the Phillies hope Hamels can finally parley a strong effort against the Nationals into a win as the teams play the middle game of their series Tuesday night.

Though it has the worst record in baseball, Washington (53-85) has been able to put together the longest current winning streak in baseball. The Nationals won their seventh straight game Monday, beating the Phillies 9-4 to drop Philadelphia (75-63) two games behind the NL East-leading New York Mets.

“We’re going through one of those good times now,” Washington third baseman Ryan Zimmerman said. “We’ve got to keep doing that for the rest of the month and it’ll be a fun last three or four weeks.”

The Phillies, meanwhile, had to be hoping a series with the Nationals would boost their chances of catching the Mets, but they’ve now lost four of their last six.

“We’re not gonna let this one game get us down,” Philadelphia second baseman Chase Utley said. “We’re gonna battle back like we always have. This month is obviously extremely important so we’ll see what happens.”

Putting Hamels (11-8, 3.13 ERA) on the mound seems to give the Phillies a good chance to end their funk, but two of his best starts of the season weren’t enough to beat the Nationals. Philadelphia lost both of Hamels starts against Washington 1-0, with the left-hander boasting a .164 opponents batting average and striking out 17 in 15 innings.

He is 4-3 with a 2.25 ERA in 11 career starts versus the Nationals.

Hamels’ pitch count might be limited in this game because the Phillies are considering using him on four days’ rest against the Mets on Sunday, according to the team’s official Web site. He is 2-1 with a 2.04 ERA in his last five starts.

In his last outing, Hamels gave up one run and five hits in seven innings against the Chicago Cubs on Thursday night, but the Phillies lost 6-4.

Washington will counter with John Lannan (8-12, 3.92), who is 0-1 with a 9.00 ERA in two career starts versus Philadelphia.

The left-hander earned a win in his last start, allowing two runs and four hits in six innings as Washington beat the Los Angeles Dodgers 11-2 on Thursday night. He won at Washington after losing his previous two outings there, posting a 13.03 ERA.

Lannan will be trying to help the Nationals extend their best winning streak since a 10-game run in June 2005. Every Washington starter had at least one hit Monday, and the Nationals are batting .336 while averaging 7.8 runs over their last six games.

“That’s what we’ve been missing the whole season,” Washington manager Manny Acta said. “Now guys are swinging the bats throughout the whole lineup, and it helps.”