After missing the final three games of a four-game set at Toronto over the weekend with inflammation in his lower back, Hatteberg also was kept out of this contest because he was 0-for-13 in his career against Baltimore starter Jason Johnson.
The game-winning single was just the second hit in 13 at-bats against Baltimore this season for Hatteberg. Of his last 28 RBI, 16 have either tied the game or put Oakland ahead, and 10 of those have come in the eighth inning or later.
Winning pitcher Mike Wood (2-0) tossed a scoreless top of the 12th.
John Parrish (0-1) took the loss, allowing one run, one hit, and two walks without retiring a batter.
The loss was the third straight for the Orioles, who are winless in four meetings with Oakland this season.