"Vogelsong, he's been solid all year and so consistent," manager Bruce Bochy said. "We talk about it all the time, and he goes out there and does it again. He pitched well tonight."
The Giants' first-inning offensive onslaught began with a Ryan Theriot double and a Melky Cabrera infield single, which set up Posey's RBI single to left. A Pablo Sandoval walk then loaded the bases before a run-scoring walk from Angel Pagan and an RBI forceout from Joaquin Arias.
Brandon Crawford then appeared to end the inning with a flyout to a sliding Mark Kotsay in left field, but after Bochy came out to argue the call, the umpires convened to discuss it, eventually overturning the initial ruling and giving Crawford an RBI single.
"It's a tough call," Bochy said. "You're running and trying to make the call. We knew he had short-hopped it, and it's all about getting it right, which they did. They did a great job of getting together and getting it right, which is all you can ask."
Posey's fifth-inning home run to right field plated Theriot and Cabrera, marking just the 14th time in AT&T Park history that a right-handed Giants batter homered to right field and the second time for Posey.
"I knew I got the barrel on it, but when I saw Kotsay keep drifting, I thought it was going to go off the wall," Posey said. "I was even happier when it went over."
The Giants' All-Star catcher has a Major League-best 17 RBIs since the All-Star break, and he is batting .513 (20-for-39) in the second half.
"Good hitters, when they're on a groove, they're fun to watch," Bochy said.
Cabrera received his share of "MVP" chants from the crowd after making a jumping catch in foul territory in the sixth inning, falling into the seats along the left-field line to get Kotsay out.
"He's done everything you can ask this year -- offense, defense," Bochy said. "It's a dangerous play. You hate to see him go into the seats like that. What a grab. It takes great focus to grab a ball like that, and that's the way he plays."
The All-Star left fielder also went 3-for-4 at the plate with two runs scored.
"I always play hard because I want to help the team any way I can," Cabrera said through an interpreter.
Nate Schierholtz also made a sprinting catch near the right-field corner on a Logan Forsythe shot in the fifth inning, and Sandoval made a diving stop at first base to prevent a run in the fourth inning.
Crawford was involved in another peculiar play in the sixth inning that involved the umpires when he appeared to hit a double to center field, only to be called out by first-base umpire Jordan Baker because he didn't touch first base.
"He said he saw him miss it," Bochy said of his conversation with Baker when he went out on the field to argue. "You've got to be positive there before you make that call, and he said he was. You can't blame Brandon for being upset. I don't think you can make that call unless you're absolutely positive."
Crawford was later ejected by Baker after he grounded out to first to end the eighth inning.
"I just asked him if I touched it that time," Crawford said. "I might have touched the base a little harder than usual. I didn't think I said anything worthy of being tossed."
After falling behind several batters in the early innings, Vogelsong settled down to record his 15th straight quality start, improving his National League-best home ERA to 1.41.
"I was struggling with my two-seamer, which is pretty uncommon," Vogelsong said. "That's usually the one pitch I can go to most of the time. I think I was pushing it, trying to do too much. But overall, I felt pretty good."