By JON PALMIERI
(AP) -- Dismissing the early-season success of the Baltimore Orioles is understandable given how the team has performed since its last winning campaign 15 years ago.
While wins in any form would be enough to silence some skeptics, the manner in which the club is succeeding should help to turn even more non-believers.
The Orioles have won four straight overall and eight in a row on the road, streaks the AL East leaders seek to continue Saturday night against the Washington Nationals.
The start of interleague play didn't slow the surprising Orioles, who beat the Nationals 2-1 in Friday's series opener on Nick Markakis' home run in the 11th inning. Jake Arrieta pitched one-run ball over seven innings and Baltimore's major league-leading bullpen lowered its ERA to 2.07 with four scoreless frames.
With its fourth consecutive win, Baltimore (26-14) moved 12 games above .500 for the first time since June 2005 - the last year it led the East this late into a season. Baltimore is a major league-best 14-5 on the road, where it has won eight in a row for the time since a 10-game run in 1999.
The Orioles also have won six straight in extra innings - all on the road.
"Hopefully, it bodes well mentally," manager Buck Showalter said of his team's late-game heroics. "When you get in those situations that you've been there and handled it well because, especially on the road, there's such a finality to that bottom of the inning. But the key is our guys are playing pretty loose through that. They have a lot of confidence in close ballgames."
Improved starting pitching may be the biggest reason for Baltimore's improvement, and offseason acquisition Jason Hammel has played a key role. He's won four of five decisions and his 2.68 ERA ranks among the AL leaders.
Hammel, though, is coming off his least effective outing.
Bidding to become the first pitcher in Orioles history to open a season by allowing two runs or fewer in seven consecutive starts, the right-hander instead gave up five runs and seven hits over five innings Monday against the Yankees. Hammel, whose start was pushed back four days due to a sore knee, tied a season high with three walks and matched a season low with three strikeouts before leaving without a decision.
"I felt fatigue from just not being on my feet," Hammel told the Orioles' official website. "But other than that, no pain, no soreness or stiffness."
He's 3-0 with a 3.55 ERA in five career starts against the Nationals.
Baltimore starters have been very good since Hammel's last outing, compiling a 2.67 ERA during the four-game winning streak.
The Nationals, who have dropped two straight at home for the first time this season, are missing three starting position players - outfielders Michael Morse (lat) and Jayson Werth (wrist), and catcher Wilson Ramos (torn right ACL).
"When you're missing some key guys, it puts pressure on some other guys to be more aggressive and be more run-producing," manager Davey Johnson said.
Orioles catcher Matt Wieters went hitless in five at-bats Friday and is 4 for 36 in his last nine games. He's batting .191 (9 for 47) with one extra-base hit in 13 career games against Washington (23-16).
Wieters has walked in his only two plate appearances against the Nationals' Ross Detwiler (3-2, 2.75), who's also coming off his worst start of the season.
After yielding three earned runs or fewer in his first six outings, the left-hander was reached for five - four earned - and seven hits over five innings against San Diego on Monday. Detwiler was in line to lose his second consecutive start before the Nationals rallied for an 8-5 victory.
He has made two starts against the Orioles - both in 2009 - going 0-1 with a 4.91 ERA.
Updated May 19, 2012