That's why paper is so disposable. Cain (12-4) worked seven innings and surrendered all of Cincinnati's five runs, one more than the number of earned runs he had yielded in his previous seven home starts combined. Harang (6-13) allowed just two Giants to reach second base in the first seven innings.
"It's a series that you think that we should win," Cain said. "We just didn't get it done. Our pitching let us down."
In fact, the Giants lost both games started by their prized 12-game winners, Cain and Tim Lincecum, though the latter received no decision after departing Friday's encounter with a 5-3 lead.
The Giants squandered a chance to gain ground on the Los Angeles Dodgers, whom they trail by 5 1/2 games in the National League West. San Francisco begins a three-game series against the first-place Dodgers at AT&T Park on Monday. Meanwhile, the Giants fell back into a tie with Colorado for the NL Wild Card lead.
San Francisco also must dwell on the health of center fielder Aaron Rowand, who left the game after six innings with a tight left hamstring. Rowand made a spectacular diving catch of Brandon Phillips' fifth-inning line drive but felt discomfort as he pursued a fly ball hit by the next batter, Joey Votto. Warned by head athletic trainer Dave Groeschner that he could put himself on the 15-day disabled list if his hamstring popped, Rowand played just one more inning.
"He said be smart about it," Rowand said.
By the time Rowand departed, Cincinnati appeared to be in complete control with a 5-1 lead. Phillips' two-out home run in the first inning and Adam Rosales' two-run homer in the fourth highlighted the Reds' offense. Rosales, a rookie who entered the game batting .211, was an unlikely tormentor. But Cain said that the 2-1 pitch Rosales hammered "ran right back over the middle of the plate, kind of in his happy area." The two long balls equaled the number of homers Cain surrendered in his previous seven home starts.
Wladimir Balantien also helped the Reds, singling and scoring in the fourth inning and singling again to drive in a run in the fifth.
The Giants had isolated opportunities to change their fortunes. But Pablo Sandoval, their best all-around hitter, twice grounded into double plays at critical junctures -- with runners at the corners and nobody out in the sixth inning against Harang, then with the bases loaded and nobody out in the eighth against right-handed reliever Nick Masset.
Give Sandoval a break, Giants catcher Bengie Molina urged.
"What can you say about Pablo? When is he going to do that again? Probably never," Molina said. "That kid has been carrying us for so long. I'm sure he'll win the game for us tomorrow or the next day."
Facing Masset as the potential tying run, Sandoval swung on the first pitch and grounded it to second base. Spectators groaned, but neither club's manager second-guessed the 22-year-old.
"Most of the time that first pitch is going to be the best pitch to hit," Cincinnati's Dusty Baker said. "I have nothing bad to say about him swinging at the first pitch. This guy has had success doing that all year. That's why he's hitting .330-something."
Said San Francisco's Bruce Bochy with an emphasis that prompted laughter, "I don't want Pablo taking anything
. If there's something there he likes, that's Pablo. No way we're going to change that. We had the right guy up there, and he got out in front of [the pitch]."