Despite allowing a double to the first batter he faced and walking the bases loaded in the second inning, Cain silenced New York for six innings. He threw 50 pitches in the first two innings and appeared destined for an early exit, yet surrendered just three hits to the Mets, who batted .359 (42-for-117) and scored 24 runs in the series' first three games.
Cain, who has worked at least six innings in all eight of his starts, also drove in a run with a fifth-inning single, then executed a rugged takeout slide at second base to break up a double play.
"That's something the club feeds off," Giants manager Bruce Bochy said.
The Mets' dominance, coupled with San Francisco's four-game losing streak overall, ratcheted up the Giants' resolve a notch or two. After Brian Wilson finished a perfect ninth inning to rebound from losing the series' first two games and record his ninth save, nobody in the Giants' clubhouse spewed any of those each-game-is-equally-important cliches.
"Some wins are bigger than others, and there's no question we needed to win this ballgame," Bochy said.
"The way they beat us the last few games, we really needed to pull that one out," left-hander Jeremy Affeldt said.
Cain (4-1) set the Giants' course, stranding Alex Cora on third base by retiring Carlos Beltran and Gary Sheffield to end the first inning. The right-hander outdid himself in the second inning -- though he nearly undid himself -- by coaxing Jeremy Reed's double-play grounder after his trio of walks. First baseman Travis Ishikawa started the play by firing the ball home, then pumped his fist in exultation after taking catcher Bengie Molina's return throw.
"We had a 1-0 lead at the time; we needed to make a play," Ishikawa said, explaining his uncharacteristic outburst. "Anytime you keep any run off the board, it's huge. I was just really excited to make the play for [Cain]."
Cain provided the excitement in the fifth inning with Aaron Rowand on second base and one out. After fouling off a 2-1 pitch from Mets starter Mike Pelfrey (4-1) on a squeeze-bunt attempt, Cain singled home Rowand on a 3-2 delivery. For emphasis, Cain barreled into shortstop Fernando Tatis on Eugenio Velez's subsequent grounder, helping Velez reach first safely.
"Once you're on the bases, you're trying to be a baserunner again," Cain said. "It's one of the things we harp on."
The Giants mustered their only other run in the first inning as Pablo Sandoval drilled a two-out single, advanced on the first of Pelfrey's three balks and scored on Bengie Molina's single.
So the Giants didn't have much of a lead to protect after Cain departed. But after Bob Howry handled the seventh inning, Affeldt wiggled out of a bases-loaded, one-out jam by inducing Angel Pagan's double-play grounder.
Sealing New York's first shutout was up to Wilson, who yielded three ninth-inning runs with the score tied, 4-4, in Thursday's series opener. Friday, he entered the ninth amid a 6-6 deadlock and allowed two runs.
This time, he completed his task with an absence of drama but an excess of inspiration, provided by Giants partisans in the season's biggest paid crowd (43,012) -- the weekend's third consecutive sellout at AT&T Park.
"You could definitely tell the crowd today was vibrant. You could feel their emotion while you were on the mound," Wilson said. "Normally I drown things out, but you can always get a boost of confidence when you hear your home crowd cheering and getting into the game."