SAN FRANCISCO — Nate Schierholtz put down his head and kept running. Matt Cain didn't want to call it quits, either.

Together, they kicked the A's halfway back to Yerba Buena Island.

Since their last playoff season in 2003, the Giants haven't had many weekends as satisfying as this one, which ended Sunday with a 7-1 victory and a three-game sweep over their Bay Bridge rivals.

Cain tossed a four-hit complete game, Pablo Sandoval hit a conventional home run, and Schierholtz made his homer a little more exciting, sprinting around the bases for an inside-the-park job as the Giants won for the 15th time in 21 games.

The Giants are six games over .500 for the first time in Manager Bruce Bochy's three seasons on the bench. It's the club's best mark since they finished 2004 with a 91-71 record.

They also swept the A's in a three-game series for the first time since 2001, which also happens to be the last time they won the Bay Bridge season series.

Perhaps most significantly, they have re-established a home-field advantage at AT&T Park. Their 21-9 home record is the third best in the majors, trailing only the Los Angeles Dodgers and the Boston Red Sox.

And while it's early, they lead the N.L. wild-card standings.

Anyone want to trade in that split Giants/A's cap for an all-black model?

"It's a fun rivalry, playing these guys," said Cain (9-1), who shares the N.L. lead in victories with the Dodgers' Chad Billingsley. "For sure, we definitely feel confident. It's all clicking right now."

Cain punched the pocket of his glove after striking out Jason Giambi to clinch his N.L.-best third complete game of the season. One of the three came in a rain-shortened game at Washington, but it's notable that only Kansas City's Zack Greinke (five) has completed more.

The question isn't whether Cain will make the N.L. All-Star team, but whether he could start the July 14 game in St. Louis.

"Could he? Sure, he could," Bochy said. "It's been a pleasure to see his progress as a pitcher. He's getting rewarded for all the work he's put in. He felt so good and wanted to finish so badly, so we let him go. He was locked in, and he maintained it through the ninth. It tells you his strength."

Cain was popping the radar gun at 95 mph in the ninth inning. He threw 119 pitches and didn't walk a batter while striking out nine.

"I feel comfortable pitching in close games," said Cain, "but these guys are giving me plenty of support."

Sandoval's two-run homer capped a three-run first inning. The Giants added more in the third after Sandoval drew a four-pitch walk from Brett Anderson with two out. Rich Aurilia singled and Schierholtz hit a towering shot that bounced off the warning track in front of the right-field arcade. The ball took a hard bounce in the air and right fielder Jack Cust, a misplaced designated hitter, took his time gathering it up.

Schierholtz was thinking triple out of the box. When he saw third-base coach Tim Flannery, he knew he had 90 more feet to negotiate.

"Where else can a 51-year-old get that kind of adrenaline hit?" said Flannery, who knew it would take two long throws to make a play develop at the plate. "I just greeted him and said, 'Let's go.' "

Bochy won't put up a stop sign Monday. He said he plans to start Schierholtz against the Angels' John Lackey.

Even if Schierholtz doesn't hit an inside-the-parker every day, his solid defense — he had two notable assists on impressive throws during the series — makes him a clear upgrade over struggling Fred Lewis.