(Sports Network) - The Baltimore Orioles take aim at their fourth straight win this evening when they continue their three-game interleague series with the Washington Nationals at Camden Yards.

In the opener of this set on Friday, Brian Roberts went 2-for-4 with a triple, and the Baltimore bullpen threw four scoreless innings in a 5-3 victory.

Melvin Mora, who missed the past two games with a sore shoulder, doubled and batted in a run, while Nick Markakis and Kevin Millar each had an RBI. Luke Scott hit a solo homer for Baltimore, which has won six of its last seven.

Garrett Olson (3-0) gave up three runs on nine hits in five innings, and struck out three, while Matt Albers threw two-plus scoreless innings of relief. George Sherrill tossed a perfect ninth for his 16th save of the season.

Ryan Zimmerman had three hits and two RBI, while Lastings Milledge and Jesus Flores each had two base-hits, but the Nationals had a two-game win streak snapped.

Shawn Hill (0-1) took the loss after allowing five runs -- four earned -- on eight hits in five frames.

Hoping to keep the O's in the win column this evening will be lefty Brian Burres, who has lost his last three starts. Burres fell to 3-4 on the season on Sunday in Kansas City, as the Royals tagged him for four runs and nine hits in six innings.

Burres, who has pitched to a 3.59 ERA this season, will be making his first start against the Nats tonight. He has thrown 1 1/3 scoreless innings in relief against them, though.

Washington will counter with veteran lefty Odalis Perez, who is unbeaten in his last five starts. Perez earned his first win of the season on Monday against the New York Mets, as he allowed four runs and 11 hits in 6 1/3 innings to improve to 1-3 on the season to go along with a 3.71 ERA.

Perez is 2-0 lifetime versus the O's with a 2.70 ERA in three starts.

Washington took four of six in last year's edition of the Beltway Series.

Baltimore was just 6-12 in interleague action a year ago, while Washington split its 18 games with the Junior Circuit. The O's also lost eight of their nine interleague games at home.