BALTIMORE -- A year ago, Dallas Braden was trying to recover from a serious shoulder injury. Earlier this month, the left-hander was pitching in Double-A for the Midland RockHounds.
Braden pitched six innings of three-hit ball to win his major league debut, and the Athletics beat the bumbling Orioles 4-2 Tuesday for a two-game sweep.
Braden (1-0) gave up one run, struck out six and issued only one walk -- to his first batter. Called up from Triple-A Sacramento on Monday, he permitted only one runner past second base in becoming the first Oakland starter to win in his big league debut since Aaron Harang in 2002.
"It's hard to pitch on a cloud, but I tried to find a way to do it," he said. "To be here now is a dream come true, as cliche as it might sound. ... It's amazing."
Braden pitched in only 10 minor league games last season after recovering from a humoral defect in his left shoulder. He allowed only three runs in three games this season before being summoned to fill in for Rich Harden, who was placed on the disabled list Monday.
"If you told me that was going to happen this soon, I'd have called you a liar," he said. "But I felt healthy. That's what they told me at the beginning of the season, that if I get healthy, I can pitch. Then if I do what I can do, then maybe I'll get a shot."
The Orioles never got more than one batter on base in any inning against the 23-year-old.
"He mixes his pitches up," outfielder Jay Payton said. "It's one of those things, the unknown, when you don't know the guy and he comes in with his A-game."
A's starters have allowed one run or less in seven of eight games. It was the 18th consecutive game in which an Oakland starter gave up three runs or fewer, the longest such streak since Cleveland went 18 straight in 1998.
Huston Street, the fourth Oakland reliever, worked a perfect ninth for his sixth save.
Aubrey Huff drove in a run and scored one for the Orioles, who began the series with a four-game winning streak.
Baltimore committed two mental errors that led to three Oakland runs. Melvin Mora botched a grounder to third and then failed to cover the base in the first inning, and Brian Roberts threw to the wrong base in the sixth.
"There's no guarantee that we would have won, but those are mistakes we can't have," Payton said. "Those are the kind of mistakes that teams that finish under .500 make."
Oakland outfielder Nick Swisher was removed in the first inning with a strained left hamstring. Swisher was rounding third when his leg buckled, and he had to crawl back to the base before being helped to the dugout.
"It's no big deal. I'll check it out tomorrow and hopefully be back in the lineup as quick as I can," Swisher said. "I feel fine."
In the bottom half, Oakland set a major league record by keeping Baltimore scoreless. It was the 20th straight game in which the A's failed to allow a first-inning run, a record for the start of the season. The previous mark of 19 was held by the 1990 Milwaukee Brewers and 2005 Boston Red Sox, according to the Elias Sports Bureau.
Jeremy Guthrie (1-1) allowed one earned run and four hits in five innings for the Orioles. It was the second major league start for the right-hander, his first with Baltimore. After giving up two runs in the first, Guthrie yielded only one hit and a walk before being lifted after throwing 72 pitches -- 51 for strikes.
After Guthrie left, the A's scored two runs on one hit in the sixth against John Parrish to go up 4-1. With the bases loaded and two outs, Jason Kendall hit a slow roller to second at Roberts, who had an easy play at first but instead flipped the ball to shortstop Miguel Tejada too late for a force play.
"I think if we had somebody covering, he would have been out," Orioles manager Sam Perlozzo said.
Either way, the Orioles should have been out of the inning. Parrish, who entered with a spotless ERA, then forced in a run by walking Danny Putnam.
Successive doubles by Tejada and Huff off Jay Witasick made it 4-2 in the seventh.
Oakland went up 2-0 in the first. Swisher hit a one-out single and moved up on a wild pitch before Eric Chavez singled. After Swisher pulled up at third, Mora botched Mike Piazza's potential double-play grounder to third, allowing pinch-runner Marco Scutaro to score. Chavez took third while Mora lamented his mistake, and Todd Walker followed with a sacrifice fly.
Baltimore got a run in the second when Huff tripled and came home on a grounder by Payton.
That was the extent of the damage against Braden, who left after throwing 86 pitches.
"It was tough taking him out, really. He was pitching so well," Oakland manager Bob Geren said, "But he had gotten to that point in the game where I felt like he did his job. With the physical and emotional end of pitching his first game, I felt like he had enough."
- The A's have won 13 of their last 15 at Camden Yards.
- Baltimore placed RHP Scott Williamson on the 15-day DL and recalled RHP Jim Johnson from Triple-A Norfolk.