Josh Donaldson hit a two-run home run and Yoenis Cespedes added a two-run double as the A's claimed the opener of a four-game series against Giants on Monday.

Those big hits backed starter Dan Straily and two relievers as the A's limited the National League's top hitting team to four singles in a 4-1 victory at the Coliseum.

Donaldson kept his hot streak going in front of a Memorial Day sellout crowd of 36,067. The emerging All-Star candidate followed Cespedes' fourth-inning walk with a drive over the right-center-field wall for his eight home run of the season.

It was the first hit of the game off Giants left-hander Madison Bumgarner and it provided a 2-0 lead. Donaldson has six home runs and 25 RBIs over his past 33 games.

The Giants' run came on Buster Posey's RBI groundout in the sixth to make it 2-1. It marked the first run Straily had given up in 16 innings.

San Francisco opened the day with a .272 batting average, tops in the league.

Cespedes greeted reliever George Kontos in the seventh inning by doubling home two more runs to make it 4-1. All of the runs were charged to Bumgarner, who gave up four runs in 62/3 innings.