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Trying to get back into the NL East race, the Washington Nationals need to do a lot better this time against the Miami Marlins.

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Good thing the club's offense appears capable.

The Nationals look to continue their recent turnaround Thursday night in the opener of this four-game set with the Marlins.

Washington (75-70) is second in the division, 7 1/2 games behind the New York Mets. The Nationals have gained some ground with a four-game winning streak, averaging 7.3 runs and hitting .325 with 10 homers. That marks a tremendous improvement after they lost five straight with a .232 average, three homers and 3.2 runs per contest.

That poor stretch included two defeats at Miami (63-83) last weekend before the Nationals concluded the series with Sunday's 5-0 victory to begin their win streak.

They showed off some power Wednesday as Jayson Werth hit two solo homers and Bryce Harper added a two-run blast - his 40th of the season - in a 12-2 win over Philadelphia.

"We have to keep grinding and keep winning," said Harper, who went 7 for 13 with four homers and seven RBIs in the three-game series after going 1 for 8 with five strikeouts in three meetings with Miami.

Werth was 2 for 10 in that series but bounced back by going 5 for 13 with four homers and seven RBIs against the Phillies.

Harper sits atop the majors with a career-best .338 average, while his 40 homers are among the leaders and make him just the third in franchise history to reach the mark and first since Alfonso Soriano's team-record 46 in 2006.

"He plays hard, plays like he's having fun," left-hander Gio Gonzalez said. "It's just unbelievable and fun to watch. To say the sky's the limit is an understatement."

The offense didn't come through for Tanner Roark (4-5, 4.38 ERA) in Saturday's 2-0 loss to the Marlins. The right-hander yielded two runs in 4 2-3 innings, dropping to 2-2 with a 2.62 ERA in five starts against them.

Roark is 3-2 with a 5.06 ERA in eight starts on the season, but he's allowed three runs in nine innings over his last two after replacing Joe Ross in the rotation.

The Marlins have won 11 of their past 15 games, taking five consecutive series to tie a team record set in 2003.

"The thing for me that makes me the most proud is that these guys are playing the game the right way," manager Dan Jennings said after Wednesday's 6-0 win over the Mets. "We realize that we're not playing for the postseason but at the same time we're playing to get ready for 2016."

That's certainly true for Jarred Cosart (1-4, 4.58), who has missed much of this year with vertigo and an inner-ear infection after winning a career-high 13 games with Miami and Houston in 2014.

"I'm just trying to show them that last year wasn't a fluke," Cosart told MLB's official website. "Obviously, what I dealt with earlier this year, it changed everything."

The right-hander has allowed one run in 9 2-3 innings while not getting a decision in his last two starts. He tossed five scoreless in Friday's 2-1 win over Washington and is 0-2 with a 2.82 ERA in four starts against the Nats, getting six total runs of support.

That could change with Dee Gordon - second in the NL batting chase at .332 - looking to build on his eight hits in the last three games after going 2 for 10 against the Nationals. Gordon is a .380 hitter in his last 11 games at Washington.