SAN FRANCISCO -- Clutch hitting. Solid pitching, both from the starters and the bullpen. Flawless defense.

It was exactly what the San Francisco Giants, riding a three-game winning streak through the weekend, expected when they returned home Monday to begin a weeklong homestand.

However, they didn't expect it from the San Diego Padres.

Right-hander Luis Perdomo pitched into the seventh inning and the bullpen threw hitless ball the rest of the way as the Padres completed an improbable three-game sweep of the Giants with a 3-1 victory Wednesday afternoon.

The loss by the Giants (77-68) not only hurt their chances of catching the Los Angeles Dodgers in the National League West but also kept them from putting a little distance between themselves and their primary competition for a wild-card playoff spot -- the New York Mets (77-69) and St. Louis Cardinals (76-69).

Both the Mets and Cardinals lost Wednesday, too.

Giants manager Bruce Bochy was asked if he is looking forward to the big four-game series against the Cardinals that begins Thursday night in San Francisco.

"This was a big series," he said of the set against the Padres. "We needed to come home after that big series in Arizona and play well."

They didn't. The Giants hit just 21-for-97 (.216) in games started by the likes of Paul Clemens, Clayton Richard and Perdomo.

"We got shut down in the first game (4-0) and shut down today," Bochy noted. "That's something I didn't see (coming)."

Luis Sardinas had three hits, scored twice and drove in a run for the Padres, who have won six straight against the Giants after losing their first nine contests against San Francisco this season.

The three-game sweep was San Diego's first in San Francisco since May 2010.

"The biggest thing is the fact they were all team wins," Sardinas said. "We're all playing together; we're pretty united at this point. I think that's what we showed in this series, and that's the key for any team to have success."

Perdomo (8-9) rebounded from two poor September starts to stymie the Giants on four hits over 6 1/3 innings. He allowed one run, walked one and struck out five.

Perdomo had been roughed up for nine runs and 17 hits over 12 2/3 innings by the Dodgers and Colorado Rockies in his two previous starts.

"Lack of fear, that's been the most impressive thing," Sardinas said of Perdomo. "Then on our end, we can help him by being ready ... knowing that he's going to induce ground balls."

The Padres played error-free ball the entire series.

Perdomo left with one on and one out in the seventh and holding a 3-1 lead, and watched the San Diego bullpen dominate the Giants from there.

Brad Hand struck out the only two batters he faced to finish the seventh. Fellow left-hander Ryan Buchter recorded two strikeouts in a scoreless eighth, and righty Brandon Maurer pitched a 1-2-3 ninth for his 10th save.

The win was the Padres' 50th straight this season when leading after eight innings.

San Diego got the better of Giants ace Madison Bumgarner, who allowed three runs in 6 2/3 innings.

"He's been in the big leagues for some time now," Perdomo said. "He's a beast."

Sardinas helped San Diego jump on Bumgarner for a run in the first inning. He singled with one out, went to third on Wil Myers' double and scored on Yangervis Solarte's infield out.

The Giants got even in the second with their only run against Perdomo, taking advantage of a leadoff walk to Brandon Crawford. Joe Panik drove in the run with a one-out single.

Sardinas' second hit, another single, came in the sixth. After he stole second, he came home with the eventual difference-making run on Alex Dickerson's two-out RBI single.

San Diego tacked on in the seventh and sent Bumgarner to the showers.

Adam Rosales led off the inning with a double and scored on Sardinas' third single, a two-out hit that ended Bumgarner's day.

In losing to the Padres for the first time in his last five home starts, Bumgarner (14-9) allowed seven hits and two walks. He struck out five.

"Tough luck. No other way to describe it," Bumgarner said of his loss. "I made some good pitches."

The Padres out-hit the Giants 8-4, with all of San Francisco's hits being singles.

NOTES: Padres SS Luis Sardinas went 7-for-14 with four runs and two RBIs in the series. He is batting .458 (11-for-24) during a six-game hitting streak. ... Padres LHP Brad Hand's two strikeouts gave him 100 for the season. Only five previous San Diego relievers reached the milestone. ... The Giants were swept for the fourth time since the All-Star break. ... When he completed the top of the first, Giants LHP Madison Bumgarner went over 200 innings for the sixth consecutive season. ... San Francisco has re-evaluated 3B Eduardo Nunez and is now calling his injury an oblique strain. Manager Bruce Bochy said he hopes to have Nunez back for the St. Louis series that starts Thursday. ... San Francisco reinstated RHP Derek Law (strained elbow) from the disabled list. He became the 35th active player on the San Francisco roster, with 20 being pitchers.