SAN FRANCISCO -- Watching the Giants on Sunday felt like summer again.

Mostly freed from the burdensome demands of the pennant race, which they barely cling to mathematically, the Giants performed as they did to become contenders in a 5-1 victory over the Chicago Cubs.

Matt Cain interrupted a prolonged slump by allowing three hits in eight shutout innings. Every starting position player contributed at least one hit to the 14-hit outburst, and Cain laid down three sacrifice bunts. Even the fans, who seemed so tentative about cheering earlier in this series while the Giants dropped back in the National League Wild Card race, regained their vocal vigor.

Now that a lot of people can't wait for the season to end, along came a day that made one wish it wouldn't.

"It seemed like everybody was pretty loose today," said catcher Eli Whiteside, who lined a pair of RBI doubles. "I just told myself to go out and have fun today. Maybe that's what the other guys did as well."

Officially, the Giants remain in the postseason hunt. They trail Colorado by five games with six to play for each team. But manager Bruce Bochy emphasized that even if the Giants were eliminated, they must continue to strive for efforts such as Sunday's.

"We do have an obligation to the fans and organization to finish strong and play good baseball," Bochy said. "We did that today."

Cain led the way by reversing his recent form. He was 1-5 with a 4.87 ERA in his previous 10 starts, including 0-3, 9.42 in his last three outings. By contrast, the Cubs saw the Cain who earned NL All-Star status, throwing his entire variety of pitches and daring batters to hit them.

Asked if his struggles had resulted from pushing himself to further the Giants' postseason bid or secure his elusive career-high 14th victory, Cain said that either factor could have plagued him.

"I definitely think I was trying to put too much pressure on myself," Cain said. "... I got away from being relaxed and pitching like I did the first three-quarters of the season."

Cain acknowledged making some mechanical adjustments since his last start, a seven-run, 2 1/3-inning disaster Tuesday at Arizona. But, he summarized, "I think it just came down to being relaxed and confident and having fun out there."

That resulted in no fun for the Cubs.

"His delivery is free and easy, and boom, something nasty comes out," Chicago left fielder Bobby Scales said. "... Tip your cap to that guy today -- he's excellent."

"The ball jumps out of his hand and he's got good life on it," Cubs catcher Koyie Hill said. "He's a guy who will go out there and come after you and we just didn't have an answer today."

The Giants were more succinct.

"Today he was back to who he is," Bochy said.

"He went out and he was Matt Cain today," Whiteside echoed.

The Cubs didn't test Cain until his final inning, when he issued his only two walks with one out in the eighth. Cain retired Ryan Theriot on a fly to center, then recorded his eighth strikeout of the afternoon by fanning Kosuke Fukudome. As Cain strode off the mound, he pounded his right hand in his glove and unleased a cathartic yell.

"It just kind of came out, excitement and adrenaline and everything -- a good feeling throughout that whole game," Cain said.

With the decision, Cain (14-7) finally eclipsed his 2006 victory total. Cain called the achievement not only "nice" but also useful.

"It's one of those things where you're going to sit back in the offseason and think, 'I did this this year. What can I do to get better?'"

Sunday, not much.