Billingsley gave up a solo home run to Aaron Rowand to make the score 7-4. He then allowed an infield single to Nate Schierholtz and a laser to right field off the bat of Eugenio Velez that Andre Ethier caught for the inning's final out.
Things didn't get better for Billingsley in the ninth -- in fact, they worsened.
Billingsley gave up a two-out single, an RBI single and a walk before Dodgers manager Joe Torre pulled the plug on his night.
The lone bright spot was that the Dodgers maintained their five-game lead in the National League West as the Rockies lost on Friday, too.
But it was hard to see that rainbow as Billingsley walked off the field with his head down amid a smattering of boos from the Dodger Stadium crowd and again answered questions on why another outing went wrong.
"I just keep going out there and trying to figure something out," a visibly shaken Billingsley said after the game.
"That's all I'm doing. Tough loss today. We've got to come back tomorrow. We've got Brad Penny and Tim Lincecum going for them, so we have two big games coming up."
To his credit, Billingsley stood in front of his locker and answered every question, but most of the answers had the same common theme.
"Just trying to figure something out, that's all I'm trying to do."
Or: "It's frustrating because I'm feeling so close, and I just can't quite get it."
The events of Friday night continued a growing trend in which Billingsley will pitch well in spurts only to let it unravel later in the game.
Billingsley entered Friday with an ERA that had grown from 3.14 to 3.99 (now it's 4.05) over his past 12 starts.
His last five starts since defeating St. Louis on Aug. 18 especially have been problematic. Billingsley is 0-4 with a 5.67 ERA in that span.
Torre did his best to downplay his pitcher's troubles against the Giants.
"He just needed to go out and get some work," Torre said. "He threw a good number of pitches. He'll be on the mound Wednesday [against the Nationals]. He's been down this road too often as one of our starters to have giving up a couple runs affect anything."
Before Billingsley's meltdown in the eighth and ninth, the Dodgers and Giants were engaged in a back-and-forth battle with plenty of playoff implications.
The Giants began the day trailing the Rockies by 3 1/2 games for the NL Wild Card slot.
And once the game began, the Giants acted like a team in must-win mode.
The Giants' do-or-die approach was obvious from the get-go when Velez led off the game with a home run off Vicente Padilla.
After that, Padilla struggled to settle down and get into a groove.
Two more runners got on base in the first, but a ground ball off the bat of Bengie Molina led to an inning-ending double play.
Padilla's woes continued in the third inning, and this time he couldn't wiggle his way out of another jam.
Padilla gave up back-to-back singles to open the inning, setting the stage for Pablo Sandoval to make his mark on the game with one out.
Sandoval unloaded on the first pitch he saw for a three-run home run and a 4-1 Giants lead.
The Dodgers managed to come back and tie the game via a two-run homer by Manny Ramirez and a solo home run from Rafael Furcal, but the Giants scored two in the top of the sixth to take a 6-4 lead.
The Dodgers had opportunities in the seventh and eighth to mount a rally, and had the tying or winning run come up to the plate in both innings.
But each time the Giants' bullpen got the clutch outs necessary to preserve the win.
"They pitched better than we did -- it was probably as simple as that," Torre said. "They got a lead, we tied it, then they went up 4-1 and we tied it. We kept battling back and we had some opportunities late, but their bullpen came in and did a heck of a job."