Oakland, CA (Best E Casino) - Mark Ellis belted his third career grand slam in the bottom of the 12th inning and the Oakland Athletics avoided a three- game sweep with a 7-3 win over the Los Angeles Angels.

With one away in the 12th, Gregorio Petit broke a stretch of 15 A's batters retired with a liner over the glove of shortstop Maicer Izturis. Rajai Davis then sliced a single to right field, but Emil Brown went down on strikes. A walk to Travis Buck loaded the bases and Ellis drove the first pitch he saw from Chris Bootcheck (0-1) off the left field foul pole for his second career game-ending home run.

"We were just looking for a base hit there," Oakland manager Bob Geren said. "When the guy walked the bases loaded I knew there would be added pressure on him (Bootcheck) to throw strikes. It looked like a home run all the way but then it started curving and we held our breath."

Rich Harden gave up three runs on six hits with nine strikeouts and three walks in six innings of work for Oakland. Brad Ziegler (1-0) hurled the final 1 2/3 innings to pick up the win.

Eric Chavez finished 3-for-4 and knocked in two runs for Oakland, which has won five of its last seven games. Jack Cust walked three times and Carlos Gonzalez added an RBI single.

LA starter Ervin Santana allowed two runs on seven hits in 6 1/3 innings. The right-hander struck out nine and walked three. Darren Oliver yielded a run in one-third of an inning. Justin Speier tossed three scoreless innings in relief.

"It's tough to swallow," Bootcheck said. "The bullpen really battled and I came up short."

Vladimir Guerrero clubbed a two-run homer for the Angels, who had a season- high seven-game winning streak snapped. Gary Matthews Jr. was 2-for-4 with an RBI, while Garret Anderson had two hits and scored a run.

The A's tied the game in the bottom of the seventh. With one away in the frame, Santana was lifted for Oliver, who issued a walk to Cust. Davis entered as a pinch-runner, swiped second and trotted home when Chavez ripped a double to right field.

Matthews worked a two-out walk off Keith Foulke in the eighth, stole second and advanced to third when catcher Kurt Suzuki's throw bounced into center field. After Mike Napoli was intentionally walked, pinch-hitter Reggie Willits popped out to Suzuki in foul territory to end the frame.

Huston Street and the A's avoided trouble in the ninth. Consecutive one-out singles by Howie Kendrick and Anderson put runners on the corners. Anderson then stole second, but Street got Guerrero to fly out and fanned Torii Hunter.

In the top of the 11th, Andrew Brown, reinstated from the 15-day disabled list prior to the game, issued back-to-back walks to Izturis and Kendrick with one gone. Ziegler came on to relieve Brown, and Anderson lined into a 6-4 double play.

The A's jumped out to a 1-0 lead in the first, as Jack Hannahan doubled to open the frame and later scored on a single by Chavez.

LA pulled ahead with three runs in the top of the fourth. Anderson drew a leadoff walk and Guerrero followed with a blast to the seats in left field. Hunter then walked, stole second and came home on Matthews' RBI single.

Oakland responded with a run in the home fourth. Daric Barton hooked a leadoff double into the right field corner and scored when Gonzalez stroked a single to center.

Game Notes

It was the first walk-off grand slam for the A's since Mark McGwire accomplished the feat on June 30, 1995...Harden struck out the side in the first on nine pitches...Oakland shortstop Bobby Crosby left the game due to a slight sprain of his right ankle. He is listed as day-to-day...Athletics designated hitter/first baseman Mike Sweeney will undergo arthroscopic surgery on his inflamed left knee the club announced Sunday. The operation will be performed by team orthopedist Dr. John Frazier on Wednesday. He is expected to be out at least 4-6 weeks...To make room for Brown on the roster, the club optioned pitcher Dallas Braden to Triple-A Sacramento.