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Lefty Tony Cingrani will try to reverse the Cincinnati Reds' awful start on the road when they visit Nationals Park on Sunday for the finale of a four-game series with the Washington Nationals.

The Reds dropped their third in a row - a 6-3 verdict - in Washington on Saturday to fall to 1-8 on the road for the year.

Bryce Harper hit a two-run homer and scored two runs, Denard Span collected two hits and drove in one run and Ian Desmond had an RBI single and scored a run for the Nationals.

Starter Dan Haren (2-3) allowed two runs on six hits and struck out five over six innings in the victory.

"Much better, much better," Nationals manager Davey Johnson said. "When he's like that, he's tough."

Shin-Soo Choo hit a solo home run, while Brandon Phillips went 3-for-4 with an RBI for the Reds, who have dropped four of five overall. Starter Mike Leake (1-1) lasted just three innings and gave up four runs -- three earned -- on six hits and walked three in the setback.

Cingrani, who made three relief appearances in his big-league unveiling last season, moved into a starting role this month when Johnny Cueto was placed on the 15-day disabled list with a right lat muscle injury.

Cingrani tossed five innings of one-run ball while defeating Miami in his starting debut on April 18, then got a no-decision after allowing two runs in seven innings against the Chicago Cubs on April 23.

The Reds lost the game, 4-2.

Cingrani, who has never faced the Nationals, was a dominant 1-0 in three starts and allowed three hits and no runs over 14 innings at Triple-A Louisville before the call-up.

Washington counters with fellow lefty Ross Detwiler, who seeks a fifth straight quality start to open the season.

Winner of a career-high 10 games last season, Detwiler has started 2013 with four straight outings of at least six innings while surrendering two or fewer runs.

He got no-decisions against Cincinnati and Atlanta in his first two starts, then defeated Miami, 6-1, with seven innings of seven-hit ball on April 17.

A tough luck loss to St. Louis on April 23 came next, in which he gave up two runs in six innings of a 2-0 defeat.

Detwiler is 0-3 in his career against the Reds, but was nicked for just an unearned run in the April 6 meeting - won by Cincinnati, 7-6.

The Reds won two of three from the Nationals in a season-opening series at Cincinnati earlier this month. Washington won five of seven games with the Reds in 2012.