"He got lucky swinging the bat, but pitching-wise he was dominant," Barajas said of his batterymate. "He had electric stuff."
Billingsley (11-8) allowed two runs, struck out seven and walked two. Both runs were unearned, the result of a fourth-inning error by shortstop Rafael Furcal, who came off the disabled list earlier Friday.
"Since the beginning of the year, I was trying to find out what type of pitcher I want to be and trying to get back to what I do best," Billingsley said. "I was being aggressive with my fastball and mixing in my curveball."
Furcal misplayed a leadoff grounder by Freddy Sanchez, Aubrey Huff then singled off the glove of second baseman Ryan Theriot and both runners scored on Buster Posey's two-out single over the head of a leaping Furcal.
The Giants' two hits were their fewest since a one-hit effort July 29 against Florida.
"We've had a hard time figuring him out," Giants manager Bruce Bochy said of Billingsley. "He's been throwing the ball well. He's got good stuff and he throws hard. He's got a good cutter, curveball and changeup, and he was hitting his spots."
Billingsley pitched a complete-game 2-0 shutout against the Giants on July 21.
"He's had some pretty good games against this ballclub," Dodgers manager Joe Torre said. "Sometimes when you have that little bit of success, you get more relaxed. He was very smooth. He's back to the guy I first met here two years ago. He's got a real good look in his eye."
Hong-Chih Kuo retired the side in the ninth to earn his eighth save in nine chances.
The Giants, who had their two-game winning streak snapped, remained three games behind first-place San Diego in the NL West. The Dodgers stayed eight games behind Philadelphia in the wild-card race while ending a two-game skid.
Billingsley singled off Barry Zito (8-11) with two outs in the fourth, putting the Dodgers ahead 4-2.
"I expect that of myself," Billingsley said, jokingly.
Zito walked Matt Kemp and Casey Blake to open the inning. After getting Ronnie Belliard and Reed Johnson out, Zito intentionally walked Barajas to load the bases, setting up Billingsley to help himself. Right fielder Jose Guillen tried to field Billingsley's hit, but it rolled under his glove.
"What killed me more than anything was the two walks," Zito said.
Zito continued to scuffle, giving up four runs and four hits in four innings. He struck out five and walked four in losing his fifth consecutive start. He is 0-7 in his last 10 outings and hasn't gotten past the fourth inning in his previous four starts.
"I was making some adjustments with my delivery between starts, getting the ball down more and doing what I've got to do to make pitches," he said. "But he was pretty good on the other side."
Bochy felt he had no choice but to yank Zito early.
"We have some extra players here, which allows you to make a move like that, and I told Barry that," he said. "Barry had better stuff tonight and was a pitch away from getting out of that and staying in the game. But once we were down two in the fifth, with the added arms and position players we had, I've got to hit for him there."
Blake singled to lead off the second and scored on Barajas' homer into the left-field pavilion that gave the Dodgers a 2-0 lead. Barajas has four homers and eight RBIs in eight games since joining Dodgers in a trade from the New York Mets on Aug. 22.
"I've been smiling since day one," he said. "Being able to be productive has been great."
Billingsley had the first multi-RBI game by a Dodgers pitcher since Randy Wolf drove in two runs on Aug. 21, 2009, against the Chicago Cubs. ... Barajas was hit above his left elbow by a pitch in the seventh. He said it was sore and stiff after the game. ... The Dodgers reinstated RHP Vicente Padilla from the 15-day DL and recalled C A.J. Ellis from Triple-A Albuquerque. Furcal was in the starting lineup, batting leadoff. ... Giants RHP Chris Ray was reinstated from the 15-day DL. ... Zito hasn't won since beating the Mets 1-0 on July 16. ... Dodgers owner Frank McCourt attended the game after taking the stand in his divorce trial, which is under way in a nearby courthouse. Furcal's bat went sailing into his box, but McCourt had stepped away. No one was injured.