Indeed, Cain needed to furnish his own offense to ensure his triumph. Besides allowing only one run in seven innings, he lofted a two-run, sixth-inning homer off Cubs ace Carlos Zambrano (14-10), who happens to rank among the National League's top hitting pitchers.
"If you thought a pitcher was going to hit a home run today, I don't think Cain would have been your pick," Giants manager Bruce Bochy said.
But when maintaining poise is the issue, Cain's always a top choice.
The next foul word Cain utters about his harrowing season will be his first, which center fielder Dave Roberts referred to in praising his teammate.
"I told him this: He's going to look back on this year, and he's going to be better because of it, depending on how he handles this adversity. And I think he's handled it like a pro," said Roberts, whose two-run single off Zambrano broke a scoreless tie in the fourth inning. "So when he does reap some of the fruits of throwing well with a win, it makes you feel good."
Cain also remained calm despite throwing like Nuke LaLoosh in the bullpen.
"When he was warming up, he wasn't throwing any strikes," catcher Guillermo Rodriguez said. "I was worried about it when I walked back to the dugout. But as soon as the game started, he started pounding the corners."
Said Cain, "You try not to take too much of what goes on in the bullpen into the game. Something always changes when a hitter gets in there. It's competition."
"He's going to look back on this year, and he's going to be better because of it, depending on how he handles this adversity. And I think he's handled it like a pro."
-- Dave Roberts, on Matt Cain
Thus, Cain was primed to handle his toughest early challenge -- a second-inning confrontation against the .254-hitting Zambrano with runners on second and third and two outs. Cain fanned Zambrano on three pitches.
"You know he can handle the bat, but it's a guy who doesn't get many at-bats, so you have to say, 'I can get him out,' " Cain said. "You're thinking that you've been getting the guys out who play every day, so you try not to do anything different."
Cain received help from Rodriguez, who picked Daryle Ward off second base in the second inning. Ward lined a leadoff double before straying too far from the bag and being caught by Rodriguez's powerful throw. At the time, Rodriguez's play blunted any momentum favoring the Cubs, who won the series' first two games.
"That relaxed everything, even though I ended up walking the next guy," Cain said. "To not have [Ward] on second was a big relief. I'd rather have one out and a guy on first than nobody out and a guy on second."
That freed Cain to involve himself in the offense. He was among the three batters Zambrano walked in the fourth to load the bases with two outs. Roberts then rocked Zambrano with his key hit, which he dumped into right field one pitch after plate umpire Kerwin Danley called a questionable strike on a 2-1 count.
"Kerwin's just doing the best he can do, as is everybody on the field," a forgiving Roberts said. "It was a pivotal pitch, but I tried to get back into the at-bat and battle."
Two innings later, Rodriguez lashed a ground-rule double with one out before Cain hoisted a 1-1 pitch into the left-field seats. It gave Cain his second home run in four starts, although he initially believed it was a routine fly ball.
"I almost thought it was one of those where I hit it real high," he said. "But I knew I caught it good, then I was thinking, 'Well, we're in San Fran, it's not going to go anywhere.' But I guess I got it up to where the wind was blowing, and it just kept going."