Hideki Matsui added a two-run single when the A’s sent 14 batters to the plate and chased Angels starter Joel Pineiro (5-4) after just one-third of an inning. Seven of the runs came before an out was recorded, a first for Oakland in its history at the Coliseum.
All-Star left-hander Gio Gonzalez (9-6) rebounded from his worst outing of the season and allowed four hits over seven innings to win for the third time in four starts.
Alberto Callaspo went 3 for 4 but the Angels, who went into the All-Star break trailing first-place Texas by one game in the AL West, didn’t do much else and dropped four games back.
Oakland went into the game as the second-lowest scoring team in the American League and had only 51 home runs — second-fewest in the majors — before Jackson’s home run landed midway up the stands in left field.
It was only Jackson’s third homer of the season and the first grand slam by an A’s player since Daric Barton had one against Seattle on Oct. 1, 2010.
To put it in perspective, Oakland had scored eight runs or more in a game only three times previously this season before the outburst against Los Angeles.
Pineiro was in trouble early on Sunday.
The Angels’ right-hander never got comfortable and walked the first three batters he faced. Matsui’s two-run single was Oakland’s first hit of the inning, but Pineiro walked Scott Sizemore.
With the infield drawn in, David DeJesus hit a sharp grounder to first base but Mark Trumbo’s throw home was wide of the plate, allowing Josh Willingham to score. Jackson then homered on an 0-1 pitch to clear the bases.
Pineiro, who hadn’t lost since June 5, retired Kurt Suzuki on a groundout but gave up a double to Cliff Pennington and an RBI single to leadoff hitter Jemile Weeks to end his afternoon.
Oakland made it 9-0 in the third when Matsui drove in Weeks, marking only the second time this season the A’s have had nine runs in a game.
Gonzalez did the rest while helping Oakland take three of four from its division rival. The A’s lone representative at the All-Star game, Gonzalez recorded his first six outs by strikeout and only allowed two runners to reach second base. He finished with eight strikeouts.
Jerry Blevins relieved Gonzalez and gave up an unearned run in the ninth on Bobby Wilson’s RBI single. That helped the Angels avoid what would have been their 11th shutout of the season.
Los Angeles had hoped to use the series with Oakland to build momentum for a critical three-game stretch at home against Texas beginning Tuesday.
After losing to the A’s for the eighth time in 13 games this season, however, the Angels face an uphill battle against the streaking Rangers.
Pineiro’s one-third of an inning is his shortest as a starter. … The Angels hadn’t allowed eight runs or more in the first inning since Sept. 3, 2000. … Matsui’s three RBIs are a season high. … Entertainer MC Hammer threw out the ceremonial first pitch and was honored with his own bobblehead doll. It was part of Oakland’s ’80s throwback day which included former pop star Taylor Dayne singing the national anthem.