© 2012 MLB Advanced Media, L.P. All rights reserved.

04/04/12 6:47 PM ET

Giants close out spring slate with loss to A's

Posey goes 2-for-2, drives in San Francisco's lone run

SAN FRANCISCO -- The A's went long for a trio of home runs in the first three innings Wednesday as they pulled away in the final game of the Bay Bridge Series against the Giants, posting an 8-1 victory at AT&T Park.

Josh Donaldson, a career catcher who will start at third base for the A's to begin the season, went 4-for-5 and smacked a two-run shot in the second and a three-run blast in the third. Jonny Gomes added a solo shot in the third, with all the homers coming off Giants Minor Leaguer Yusmeiro Petit, who took the loss.

A's starter Tommy Millone was the victor after allowing a run on two hits while striking out three in two innings.

The Giants opened up the scoring in the first when Buster Posey singled home Pablo Sandoval, who had hit a ground-rule double into the stands in left-center field. Giants manager Bruce Bochy wound up getting a lot of expected regular contributors some playing time Wednesday.

"We're ready to get the season started. I like the way the spring went. The guys worked hard, they played hard and I think we're ready," said Bochy, whose club finalized its roster before Wednesday's game.

After the A's opened up their lead against Petit, they added a pair of runs in the fifth when Anthony Recker hit a sacrifice fly and Jemile Weeks followed with an RBI single to drive home Donaldson with his third run of the game.

With the outcome of Wednesday's game, Oakland finished their exhibition schedule with a 15-7-2 mark, while San Francisco posted an 18-15-3 record this spring.

Up next: On Friday, the Giants will open the season on Friday at 4:10 p.m. PT at National League West rival Arizona, the defending division champions who dethroned the 2010 World Series winners. Two-time Cy Young Award winner Tim Lincecum will take the ball for the Giants against D-backs right-hander Ian Kennedy, a 21-game winner a year ago.

John Schlegel is a national reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.