Pittsburgh (68-85) at Arizona (88-65)

Re-establishing their success at Chase Field will move the Arizona Diamondbacks closer to an unexpected NL West title.

Extending his winning streak there may eventually earn Ian Kennedy(notes) the NL Cy Young Award.

Kennedy looks to match the longest home winning streak by an Arizona pitcher Monday night when the Diamondbacks open a three-game series with the Pittsburgh Pirates.

Arizona (88-65) ended a three-game slide with Sunday’s 5-1 victory at San Diego. The Diamondbacks lead the West by five games over second-place San Francisco with nine to play, including three head-to-head meetings at Chase Field this weekend.

Coming on the heels of back-to-back last-place finishes, Arizona has a magic number of five to clinch its first division title since 2007.

“Every victory at this point of the season is great,” said Kirk Gibson, a top candidate for NL Manager of the Year..

Another win for Kennedy (19-4, 2.99 ERA) would also be a great milestone. The right-hander is on the brink of becoming the Diamondbacks’ first 20-game winner since 2008, when Brandon Webb(notes) won the Cy Young.

Webb also is the only Arizona pitcher to win six straight home starts - a run that bridged the 2007 and 2008 seasons. Kennedy has a chance to equal that run, as he’s posted a 1.69 ERA while winning his last six outings in the desert. He’s also 11-1 with a 2.42 ERA in his last 13 starts overall.

Kennedy struggled while failing to get his 20th win Tuesday at Los Angeles, allowing four first-inning runs in a game the Diamondbacks rallied to win 5-4 in 10.

“I wasn’t commanding it as well. It wasn’t as sharp as it had been, especially with two strikes,” said Kennedy, who lasted six innings.

Kennedy didn’t get a decision in his only meeting with the Pirates on Sept. 17, 2010, allowing two runs - one earned - in six innings of a 4-3 road loss for the Diamondbacks.

Arizona rookie first baseman Paul Goldschmidt(notes) is 6 for 17 with four RBIs in his last five games. He had two hits including a homer Sunday and drove in three.

While Arizona is seeking a division crown, the Pirates (68-85) head into their final nine games looking for a positive end to a season that once saw them flirt with first place in the NL Central.

Pittsburgh has dropped eight of 10 and has been outscored 28-4 during a three-game slide after falling 15-1 to the Dodgers on Sunday.

Jeff Karstens(notes) (9-8, 3.45) takes the mound seeking his first win since beating San Francisco on Aug. 10. The right-hander is 0-2 with a 6.20 ERA in four starts since, and has been skipped twice in the rotation due to arm stiffness. He struggled upon his return Tuesday, allowing four runs and seven hits in 4 1-3 innings while not getting a decision in a 6-4 loss to St. Louis.

Karstens is 1-0 with a 2.01 ERA in six games - two starts - against the Diamondbacks. His only start at Chase Field was a two-hitter in a 2-0 win Aug. 6, 2008.