One day after his Diamondbacks clinched their first National League West title since 2007, ace Ian Kennedy will try to better his chances at a Cy Young Award.

He'll do so against a San Francisco Giants team that not only had to watch Arizona celebrate its postseason clinching, but saw its own playoff aspirations take a major blow.

Arizona's likely Game 1 starter in next weeks NL Division Series, Kennedy will make his final regular-season start in what has been an excellent 2011 campaign in tonight's second contest of a three-game series.

Kennedy won his fifth straight decision on Monday to become the National League's first 20-game winner and just the fourth in Arizona team history. He is the first Diamondback hurler to reach the mark since Brandon Webb won 22 games in 2008.

The right-hander won for the 12th time in his last 13 decisions after holding the Pirates to one hit and one walk over eight scoreless innings, matching a career high with 12 strikeouts.

"We had a nice little ceremony in there (locker room) for Ian," Diamondbacks manager Kirk Gibson said. "He deserved the win."

Kennedy is 20-4 with a 2.88 earned run average in 32 starts, winning seven straight outings at home. He is 10-2 with a 2.63 ERA in 17 starts this year at Chase Field, where he hasn't lost since May 31.

The 26-year-old Kennedy has handled the Giants very well this year, going 2-0 in four starts while allowing three earned runs with 31 strikeouts over 31 innings.

With a chance to lock up the NL West crown, Paul Goldschmidt sliced a two-run triple into right field in the eighth inning, leading the Diamondbacks to a 3-1 win. The opposite field hit got past Giants right fielder Carlos Beltran and ran all the way to the wall, allowing Ryan Roberts and Justin Upton to score to break a tie game.

"I think you can say that" it was the biggest hit of my career, Goldschmidt said of his triple. "Obviously it was a big game and I'm glad I was able to help us win."

Arizona moved to 10-5 in its last 15 but remained one game behind Milwaukee for the second-best record in the National League and home-field advantage in the first round of the playoffs.

"We set up to accomplish this first plateau," said Gibson, "and we plan on going a lot farther than this."

The Giants, after falling an insurmountable seven games back of Arizona, face a nearly impossible road to the NL wild card as well.

The reigning World Series champions are five games behind wild card-leading Atlanta with five to play after falling to 1-3 since a season-high eight-game winning streak. They would be eliminated from the postseason hunt tonight with a loss or a victory by the Braves in Washington.

"We are breathing," said Giants manager Bruce Bochy. "Five games left we are still breathing. That is why there is no need to talk. We still got baseball. We will give it our best shot tomorrow."

With no room for error, the Giants hand the ball to Eric Surkamp for the fifth time in his career and he is 2-0 with a 2.95 ERA through his first four starts.

The 24-year-old lefty won the first two games of his career -- both versus San Diego -- before lasting just 4 2/3 innings and getting a no-decision at Colorado on Saturday. Surkamp was charged with a run on three hits and six walks. He had issued five free passes over his first three starts combined.

The Diamondbacks have won six of their last eight over the Giants.