Oakland, CA (Sports Network) - Mark Ellis stroked a two-out game-winning home run in the tenth inning to give the Oakland Athletics a dramatic 6-5 win over the Baltimore Orioles.

Ellis also had a single, walk, and stolen base, while Kurt Suzuki had two hits and two runs batted in, including his first homer of the year for the A's, who completed the three-game sweep and have won four in a row overall.

Nick Markakis had three hits and Brian Roberts had two RBI in a losing effort for Baltimore, which extended its season-high losing streak to five.

Lance Cormier (0-1) came on in relief of George Sherrill in the bottom half of the tenth and a hung a two-out slider to Ellis, who drove the ball down the left field line and off the foul pole to end the contest.

In the top of the tenth, Luis Hernandez drew a two-out walk but was picked off first to end the inning with Roberts batting on a 3-1 count.

Dallas Braden (1-0) finished with 2 1/3 innings of scoreless baseball for the win.

"There's probably not a lot of people that can say they've hit a walk-off home run," Ellis said. "It's very exciting and a lot of fun to see your teammates at home plate. It's something you could play your whole career and not be able to do."

Oakland started the game off by scoring a run in the first. Suzuki led off with a single to left, and after a Daric Barton fly out, Mike Sweeney singled to right. Jack Cust drew a walk to load the bases and Emil Brown grounded out to plate Suzuki.

Ryan Sweeney led off the bottom of the fifth with a triple off the center field wall and Suzuki followed with a homer to give Oakland a 3-0 lead.

Starter Joe Blanton consistently let the O's on base but managed to work out of several jams -- Baltimore actually had the leadoff man on in four of the first five innings but failed to capitalize each time.

"This game could've been over, especially the way their bullpen has thrown but we battled back and got the lead," O's starter Jeremy Guthrie said. "We've been doing it all year. I don't think there's been any stretch where we've folded in the tent because of a deficit late in the game. We're always battling, first through the ninth inning, and it's going to come back and benefit us in the long run."

The O's finally struck in the sixth after Markakis stroked his second single of the game to lead off the frame. Luke Scott drew a one-out walk and Kevin Millar lined a single up the middle, scoring Markakis easily and moving Scott to second. Ramon Hernandez plated Scott on a two-out looping single to right and chasing Blanton after just 5 2/3 innings. Joey Devine came on for the A's and got Luis Hernandez to fly out to deep right-center to end the inning, but Baltimore had cut the lead to one.

The A's got one back in the bottom half of the sixth. Guthrie got the first two outs but surrendered a single to Ellis and was replaced after 5 2/3 innings by Jamie Walker. Walker proceeded to give up a double to Jack Hannahan that brought home Ellis to make it 4-2.

The O's managed to string together an impressive two-out rally in the eighth off the A's Andrew Brown. Millar started it off with a one-out walk before Jay Payton struck out swinging. The O's then poured it on with consecutive singles from Ramon and Luis Hernandez to load the bases. Adam Jones came on as a pinch runner for Ramon Hernandez at second before the recently inserted Roberts singled to right scoring two to tie the game at four. Melvin Mora then doubled to right, and Luis Hernandez crossed home to put Baltimore in front and chase Brown from the game. Braden came on for Oakland and retired Markakis on strikes.

The A's struck right back in the bottom of the inning by loading the bases with one out off Chad Bradford. Brown reached on a ground ball error by Mora at third and Bobby Crosby singled. Ellis laid down a sac bunt to move the runners to second and third. Bradford walked Hannahan intentionally before giving way to Sherrill. Frank Thomas came in as a pinch hitter and grounded out to score Brown and tie the game at five.