"Disappointed in what? Not at all," Cain said when asked if he felt at all crestfallen. "I couldn't care less. We needed a win today."
San Francisco and San Diego have exchanged the division lead seven times since Sept. 16, deepening the sense that next weekend's Giants-Padres three-game series at AT&T Park will determine the West champion.
"I wouldn't be surprised, as tight a race as this is," Giants manager Bruce Bochy said.
That showdown will be preceded by a three-game series against the last-place D-backs, who are 5-10 against the Giants but won two of three games in San Francisco Aug. 27-29.
Then again, the Giants demonstrated during this 4-2 trip that they could vanquish pesky opponents. They won two of three here at Coors Field, the pitchers' graveyard where Colorado owns a 52-26 record. The third-place Rockies fell 4 1/2 games behind the Giants and are virtually, though not officially, eliminated from the division race.
"To try to get them set back just a little bit was definitely a momentum-builder for us," said Cain, who recorded his fourth complete game of the season. "It seems like these guys are always hot in September. So we really, really wanted to come in here focused and win two out of three from these guys."
Cain (13-10) guaranteed that with an assertive effort that has typified his second half, during which he's 7-2 with a 2.48 ERA. One day after the Giants' 18-game streak of limiting opponents to three or fewer runs ended, Cain re-established San Francisco's pitching superiority.
Backed primarily by Freddy Sanchez, who lined a two-run homer in the first inning, and Cody Ross, who homered in the seventh, Cain retired the first 12 batters he faced. Cain spoiled his perfect game by committing a throwing error upon fielding Troy Tulowitzki's comebacker to open the fifth inning. Cain responded by striking out the side while mixing in a walk to Ryan Spilborghs. That was Cain's lone free pass of the afternoon.
Cain admitted that the Rockies "were helping me out some" by swinging at a lot of pitches early in the count. "I just kept trying to focus on keeping the ball down and throwing strikes at the bottom of the zone to let some of my offspeed stuff work later in the game," he said.
The sixth and seventh innings were much like the first four. Cain went 1-2-3 in each against the Rockies, whose grounders or fly balls never forced the Giants' defenders to make challenging plays. By the start of the eighth inning, Cain's scoreless-innings streak, spanning three games, had reached 20.
This marked the fifth time in Cain's career that he took a no-hitter into the seventh inning. Having thrown 84 pitches after seven innings, Cain was encouraged. "I think this was probably the most realistic opportunity [for a no-hitter], pitch-count wise," he said.
Ross noticed Cain's overwhelming command from his vantage point in center field. "I could see he was just clipping the outside corner and the inside corner," Ross said.
Said catcher Buster Posey, whom Cain praised lavishly, "If I wanted the ball down, it was down. If I wanted it up, it was up."
Cain, who had entered the seventh inning with a no-hitter on four previous occasions, induced a groundout to third base from Spilborghs to open the eighth. Up came Payton, who tapped a 2-0 pitch a few feet to the shortstop side of second base. Juan Uribe scooped up the ball but struggled to transfer it to his right hand. Payton clearly beat Uribe's rushed throw, and the official scorer quickly ruled the play a hit.
Interestingly, Payton's third-inning double was the only hit Cain allowed when he shut out Oakland in an Interleague game on May 21, 2006.
"I missed the ball a little bit," Uribe said, admitting that he couldn't grip it immediately. Asked if he could have thrown out Payton had he handled the ball cleanly, Uribe replied, "I think so, yeah."
Cain struck out Miguel Olivo before yielding pinch-hitter Melvin Mora's monstrous home run, halving the Giants' 4-0 lead.
Carlos Gonzalez singled with one out in the ninth, which normally would have prompted Bochy to summon Brian Wilson from the bullpen. But the All-Star closer threw 36 pitches Saturday, and though he and left-hander Javier Lopez were warming up, Bochy considered Cain his best option under the circumstances.
He was. Tulowitzki, he of the 15 homers and 40 RBIs in September, popped out. Cain spun a curveball past Jason Giambi for strike three, concluding his masterpiece.
"I thought we were going to win the game in the ninth," Rockies manager Jim Tracy said.
"No lead is safe here," Ross said. "But with Cain on the mound, it was game over."