Adrian Gonzalez hit his eighth home run off Giants loser Matt Cain (2-3), Chase Headley came through with a two-out RBI single and Kyle Blanks, mired in a 6-for-59 funk with 32 strikeouts, got hit by a pitch with the bases loaded to drive in the final run in the seventh inning as San Diego beat San Francisco for the 11th time in their last 14 meetings.
Heath Bell came on in the ninth to pick up his 11th save in 13 chances as the Padres ran their record to 17-8 against the National League West rival since the start of last season.
"Intradivision play, we play these guys so often there really are no secrets," said Padres manager Bud Black. "Clayton has matched up against these guys a number of times. We had seen Cain a ton over the years.
"The scouting reports are pretty in depth in what you think the guys are going to do so it makes it even more critical to having good stuff and making pitches. And Clayton did a good job again. He's a fastball pitcher who uses the fastball in and out. When it's down, his two-seamer has to sink to get the grounder. Secondary pitches are continuing to improve and he utilized them today. Another very solid outing."
Asked about the Padres' domination of the Giants, Black said, "I really can't say. They have a lot of great pitching and a veteran lineup and a good bullpen. I really can't explain it. But our hits are falling and they hit some balls on the nose that didn't fall."
Richard, who is 2-0 with a 1.77 ERA in three starts against the Giants, all against Cain, offered his view.
"The Giants are a tough club and a division rival. Any time we have an opportunity to win those games, it is big for us," said Richard, who is 6-1 with a 2.19 ERA in 11 starts at PETCO Park. "We're playing pretty good baseball. I know the Dodger series [the Padres were swept] was a little bit rough, but we got back on track.
"It's hard to say we've dominated -- all the games have been close, but we've made more plays, the little things, situational hitting, pitching late in the game, throwing strikes and getting ahead of the hitters.
"The first couple of times you face a team the scouting reports are huge. And we've faced the Giants so often early, we've learned and adapted from what we've seen firsthand. The scouting report goes so far and then you have to kind of adjust in what you see in a game-to-game basis and I think we've done that pretty well."
The Padres stranded 13 runners, which in some ways indicated that their offense is coming around.
"I thought, '13, OK,'" said Black. "You look at it in a positive way: 13 guys on base. We had better at-bats, drew walks, we got eight hits. I saw some approaches not expanding the zone as much. We had a couple of chances with one hit to break the game open but didn't do it, OK."
As for the Blanks hit-by-pitch that plated the insurance run in the seventh, Black said, "it was unorthodox manner but we'll take it. That's why we play, things like that happen."
The Padres have outscored the Giants 21-9 in their seven victories this season.
Cain, who pitched six innings for the Giants, is 1-8 in 15 starts against the Padres since 2007 and 4-8 lifetime with a credible 3.12 ERA.
Two fans ran onto the field in the bottom of the ninth inning and were tackled by security and taken away.