Second baseman Logan Forsythe, left fielder Chris Denorfia and center fielder Alexi Amarista each had a great catch for the Padres, who won for the eighth time in 10 games and popped above .500 for the second time this season.
"Those are three really great plays," manager Bud Black said. "You never know how a game is going to play out if another result happens. We talk a lot about defense as a group and what that means for our team, and the guys, they play their butts off on the defensive side."
The Padres continue to play well even though shortstop Everth Cabrera, first baseman Yonder Alonso and rookie second baseman Jedd Gyorko are on the disabled list, and left fielder Carlos Quentin continues to be slowed by injuries.
Ciriaco, obtained from Boston last Friday after Cabrera went on the DL, tripled in the go-ahead run in the seventh inning and hit a two-run homer in the eighth.
The defensive gems stood out.
The Padres had impressive catches against consecutive batters in the seventh. A retreating Forsythe made a sprawling catch of Mark Ellis' blooper and Denorfia tumbled over the low wall along the line to catch a foul ball by pinch hitter Elian Herrera.
In the eighth, Amarista made a great diving catch of Juan Uribe's sinking liner.
"There were a lot of great plays made tonight," Forsythe said. "On that play, I just tried to get back there."
Starter Jason Marquis called the plays "pretty special. We've been making those plays all year, no matter who's out there. That's one of the reasons we've been so successful this year -- not giving teams extra outs, making some spectacular plays and keeping guys out of scoring position. No matter who's out there, they're doing everything they can to keep guys off the bases and it makes our job a lot easier."
Even Dodgers second baseman Ellis, who committed an error in the two-run fifth, praised the Padres.
"They play very good defense," Ellis said. "They did a very good job. They obviously played better defense than we did. Obviously, my error was a huge part of the game. It changed the whole momentum of the game and gave them two runs there."
Dodgers rookie Yasiel Puig homered on his first swing at Petco Park, giving him six overall and three against the Padres since his big league debut on June 3.
The Dodgers, who've been in last place in the NL West since May 6, have lost eight of 11.
It was L.A.'s first visit to Petco Park since the teams brawled on April 11 after Zack Greinke hit Padres slugger Carlos Quentin with a pitch. Quentin rushed the mound and slammed into Greinke, breaking the pitcher's left collarbone. Greinke is scheduled to start Saturday night.
Ciriaco capped his big night with a homer to left off Peter Moylan with one out in the eighth for a 6-2 lead. It was his first with the Padres and second overall.
In the seventh, Ciriaco tripled into the gap in left-center to bring in Yasmani Grandal, who reached on a leadoff, opposite-field double down the left-field line. The ball got caught behind padding on the fence and Grandal had to hold up at second.
After Forsythe walked, Ciriaco was thrown out at home when first baseman Adrian Gonzalez raced in, scooped up Will Venable's bunt and threw to catcher A.J. Ellis for the tag. Chase Headley, who struck out in his first three at-bats, singled up the middle to bring in Forsythe.
Nick Vincent (2-0) pitched the seventh for the win.
Puig, a 22-year-old Cuban defector, drove a fastball from Marquis an estimated 406 feet into the sandy play area beyond the fence in right-center with one out in the first in his 58th big league at-bat.
Marquis was much more careful against Puig after that, striking out the phenom on sliders his next two times up.
Puig made his big league debut June 3 against the Padres, hitting two singles and making a strong throw from right field to first to complete a game-ending double play in a 2-1 Dodgers victory.
The next night, he hit two homers and drove in five runs as the Dodgers rallied to beat the Padres 9-7.
San Diego went ahead 2-1 in the fifth on consecutive RBI singles by Marquis and Forsythe. One run was unearned because of Mark Ellis' fielding error.
L.A. tied it in the sixth when Uribe's sacrifice fly brought in Hanley Ramirez.
A.J. Ellis homered off Huston Street in the ninth, his third.
Both starters went six innings.
Marquis, trying for his 10th victory, allowed two runs and seven hits, struck out five and walked one. Fife allowed two runs, one earned, and four hits, struck out six and walked one.
"We haven't seemed to be able to solve Jason Marquis," Dodgers manager Don Mattingly said. "He continues to have our number. He seems to not give in and we kind of give in and chase a little bit and help him out at times."
Puig has 28 hits in his first 16 games, tied for fourth in big league history behind Irv Waldron (31) in 1901, Joe DiMaggio (30) in 1936 and Bo Hart (29) in 2003. The Dodgers arrived in San Diego at about 3:30 a.m. after splitting a day-night doubleheader at Yankee Stadium on Wednesday. They did not take batting practice. ... Quentin, San Diego's LF, missed his sixth consecutive game with a sore shoulder. ... San Diego 1B Yonder Alonso will visit a hand specialist Monday to examine his broken right hand. Alonso has missed 14 games since suffering the injury last month. He's not expected back before the end of the month. ... Dodgers OF Scott Van Slyke (left shoulder bursitis) will begin a rehab assignment Friday at Albuquerque.