Pomeranz strugles in his first start

"His command was not quite where we saw it in spring training," Colorado manager Jim Tracy said. "I think a big part of that he struggled with his breaking ball."

Pomeranz (0-1) gave up nine hits and struck out three with one walk. He was equally disappointed with his 100-pitch outing. The 23-year-old began the season in Double A because the team didn't need a fifth starter until Sunday.

"I threw a lot of balls down the middle with my fastballs," said Pomeranz, the key player for Colorado last year in the deal that sent Ubaldo Jimenez to the Chicago Cubs. "They are a good fastball hitting team when that happens."

Tracy also disappointed watching the Diamondbacks steal four bases.

"There has to be an adjustment there," Tracy said. "You can't give them a running start like they got in two or different occasions."

Trevor Cahill earned his first win with Arizona and Chris Young homered and drove in three runs to help the Diamondbacks avoid a series sweep.

Acquired from Oakland in the offseason, Cahill (1-0) held the Rockies to four singles in 7 1-3 innings.

Last Tuesday in his Diamondbacks' debut, Cahill gave up only two hits and one run in six innings at San Diego. But he walked five and wasn't involved in the decision as Arizona won 4-2.

Cahill had little trouble with a Rockies lineup that included five bench players. He got 13 outs on groundballs, struck out six and walked two.

Aaron Hill drove in two runs for Arizona, which survived an anxious eighth and spoiled Drew Pomeranz's first start of the season for the Rockies.