Hanley Ramirez homered on Cain's first pitch. Two offerings later, rookie Alejandro De Aza tripled to right-center. Mike Jacobs soon added an RBI single to put the Giants in a 2-0 hole before many of the fans had found their seats.
But what could have devolved into a blowout quickly turned in Cain's favor. He allowed just one run and three hits over the next six innings to earn the victory in a 4-3 San Francisco win.
"You just go, 'You know what? It's alright, because it's just one pitch,'" Cain said.
It was an all-too-familiar plot for Cain, who has surrendered nearly half of his runs this season in the first inning.
"A lot of good pitchers, that first inning is the time to get them," manager Bruce Bochy said. "He's certainly a case for that. ... He's a little hyped up, he's a little quick early. I've been working on getting him slowed down, and as he goes, he does slow down a little bit.
"It happens," Bochy added. "What's important is how you handle it, and he handled it great."
And on the seventh day: With another afternoon game looming Monday and a nine-game homestand to follow before the team's next day off, Bochy sat about half of his regular starters Sunday. Barry Bonds, Ryan Klesko, Dave Roberts, Bengie Molina and Omar Vizquel were all given the day off.
Bochy said all the moves were preventative.
"We're healthy," he said. "We're fine."
This challenging stretch of the schedule has made Bochy more mindful of the lineups he'll use over the next week, he said.
"I have a pretty good idea what I'm going to have the next couple games," he said.
Lighter burden: The fishbowl around Bonds hasn't exactly vanished, as evidenced by Saturday's reported attendance of 42,817 -- the largest at Dolphin Stadium since Opening Day 2005. Still, the Giants slugger said he's felt less pressure since he broke Hank Aaron's all-time home run record Aug. 7.
"It's different," Bonds said. "You go out there and just concentrate on baseball. You don't have the whole magnitude of everything going on around you and the whole team."
But Bonds, who now needs just one RBI to move past Babe Ruth for sole possession of third place on the all-time list, also said it's not time to take his foot too far off the gas pedal.
"You don't want to tank it," he joked, "because all our games are on TV."
Settling in: Brian Wilson has posted a solid first week, tossing a scoreless inning Saturday for the third consecutive night.
The 6-foot-1 right-hander was called up on Aug. 11 from Triple-A Fresno, where he posted a 2.10 ERA, 37 strikeouts and 11 saves in 34 1/3 innings.
"He's been impressive," Bochy said.
Also notable to Bochy is that three of Wilson's appearances have come over the last three nights.
"That's a big part of relieving," Bochy said, "not just having the stuff for one game, but being able to go out there three days in a row and still have the stuff to get hitters out."
Back with a vengeance: Rich Aurilia has been in the lineup for all three games since his return from the disabled list.
"I want to get him early consistent at-bats," Bochy said. "We'll see how he's doing after the game today. We might give him a day [Monday]."
On deck: The Giants will wrap up their four-game series with the Marlins at 10:05 a.m. PT Monday. Russ Ortiz (2-3, 5.20 ERA) will oppose sinkerballer Sergio Mitre (4-7, 4.90 ERA).
Tom Keller is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.