SAN FRANCISCO -- The A's day started with news that third baseman Eric Chavez was scheduled for season-ending back surgery. It ended with Jason Giambi striking out against Matt Cain, the final out in a 7-1 loss Sunday to the Giants.

The A's recent seven-game winning streak, power surge and good vibes are officially ancient history. They lost three straight to the Giants in the Bay Bridge Series and have dropped five of their past six games.

During their seven-game streak, the A's averaged six runs per game. During their past six games they've averaged 2.3. They totaled three runs in three games against the Giants, losing to Tim Lincecum, Randy Johnson and now Cain.

"Are our guys struggling or were those well-pitched games?" A's manager Bob Geren said. "That's the debate. Lincecum was about as good as I've seen him and so was Cain. Johnson, we had a few chances to score but not a whole heck of a lot.

"That's their strength over here, and they showed it this weekend."

Cain pitched a complete game, striking out eight and walking none. He improved his record to 9-1, lowered his ERA to 2.39 and continued making his case for a spot on the National League All-Star team, where Lincecum will likely wind up.

"He was great," Giambi said of Cain. "He threw everything for a strike. ... He pitched up in the strike zone. His offspeed [stuff] was great. He didn't make a lot of mistakes. He's definitely having a great year.

"Definitely great pitching is going to stop hitting," Giambi said of the series. "We weren't swinging the bat well. They came in and they pitched great. They got the big hits when they needed them to break through. Unfortunately, we didn't. That's kind of the whole series."

A's rookie pitcher Brett Anderson didn't come close to matching Cain. He gave up eight hits, six earned runs and two home runs, a two-run shot by Pablo Sandoval in the first inning and a three-run, inside-the-park blast to Nate Schierholtz in the third.

Anderson lasted just four innings and suffered through his second straight rough outing. He gave up 10 hits and five runs to the Twins over seven innings in a loss.

"I kind of shot myself in the foot," Anderson said. "Pitched to one side of the plate. Big league hitters are going to take advantage of that after a while, and they were able to take advantage of that, jumping on some inside pitches that normally they wouldn't hit or they'd roll over and ground out. I just have to go back to throwing on both sides of the plate and kind of start from square one."

Bob Geren juggled his batting order, hoping to jump-start his offense. He moved Orlando Cabrera from leadoff to seventh. Everyone else moved up one spot, with Adam Kennedy hitting leadoff, Jack Cust second, Matt Holliday third, Giambi fourth, Kurt Suzuki fifth and Jack Hannahan sixth.

In the first inning, Cust gave the A's a 1-0 lead, launching Cain's first pitch to him into the arcade seats in right field.

That was the A's first and only lead, and it ended in the bottom of the first when the Giants scored three runs.

Giants center fielder Andres Torres led off with a bloop single down the left-field line, moved to third on Edgar Renteria's single to center and scored on Randy Winn's sacrifice fly. Anderson struck out Bengie Molina, but Pablo Sandoval crushed a 2-2 pitch deep into the left-field seats for a two-run homer.

Geren said the pitch to Sandoval was up and in, but just not as high as it should have been.

"It wasn't a total miss out over the plate," Geren said.

The Giants struck for three more runs in the third after Anderson handled the first two hitters. Sandoval walked, then Rich Aurilia hit a soft single to right, just out of the reach of a diving Cust.

Then Schierholtz hammered a high shot off the right-center wall. He turned Triples Alley into Inside-the-Park Home Runs Alley, racing around the bases as Cust chased the carom and easily beating the A's relay. It was the fourth inside-the-park homer in AT&T Park history -- one of those by Ichiro Suzuki in the 2007 All-Star Game -- and it gave the Giants a commanding 6-1 lead.

"He was flying," Cust said of Schierholtz. "I picked up the ball and he's rounding third. It was kind of a weird play."

The A's wasted a good chance to get to Cain in the second inning. With one out, Jack Hannahan ripped a shot down the right-field line, but Schierholtz gunned him down at second with a one-hop bullet to Renteria. Orlando Cabrera followed with a double, but Cain got Rajai Davis on a fly to center field, ending the inning.

So now, after a day off Monday, the A's head to Los Angeles for a three-game series against the Dodgers, hoping to recapture their hitting stroke and regain some momentum.

"That's the great thing about this game," Giambi said. "One minute you can be red-hot. The next minute you kind of fall apart. We just need to put the wheels back on and go from there."