Melvin Mora drew a one-out walk off Scott Eyre (0-1), who was replaced by Matt Herges. Hitless in his previous 14 at-bats, Miguel Tejada singled Mora to third, but Javy Lopez struck out. After Rafael Palmeiro was intentionally walked, Bigbie singled past diving center fielder Michael Tucker to end the game after 4 hours, 20 minutes.
The Orioles dropped the opener in 11 innings, 9-6, in a game that lasted just under four hours. Bigbie's second hit of the nightcap made a winner of John Parrish (5-2), who capped a solid effort by the Baltimore bullpen by working the last two innings. Five Orioles' relievers gave up two runs and three hits in seven innings.
Barry Bonds drew five of the eight walks issued by Baltimore pitchers. Four were intentional passes, but the Giants failed to take advantage as Edgardo Alfonzo was retired with runners in scoring position in the ninth and 11th innings.
Yorvit Torrealba's two-run homer off starter Erik Bedard in the second inning gave San Francisco a 2-0 lead.