PHOENIX – Colorado Rockies’ manager Walt Weiss held a team meeting before Saturday night’s game against Arizona, hoping it would provide a spark to his struggling team.

He didn’t quite get the response he expected.

Taking advantage of Colorado’s litany of mistakes in the eighth, the Diamondbacks scored nine runs in the inning to turn a close game into a 14-4 rout over the bumbling Rockies.

“I didn’t say abracadabra or anything,” said Weiss, whose team has lost eight of nine. “I didn’t say any magic words. I just tried to give them some perspective on where we are at.”

They were close at one point.

Arizona’s Trevor Cahill (2-8) did his job, overcoming a shaky defensive first inning by the Diamondbacks to win for the first time since April 23.

Jorge De La Rosa (11-8) settled down after giving up a three-run homer to Mark Trumbo in the third inning, and Nolan Arenado, who had three runs batted in, pulled Colorado within a run on a solo homer in the eighth.

By the time the bottom half was over, the Diamondbacks’ bats had exploded, and the Rockies had imploded.

The Rockies had two errors, a passed ball and a wild pitch in the inning. They also walked in a run.

The Diamondbacks fed off their mistakes and each other, lashing balls all over Chase Field.

Arizona had 15 hits, matching a team record with eight in the eighth. Alfredo Marte had a solo homer. Pennington had three hits and scored four runs. Trumbo finished with four RBIs.

David Peralta, who had a run-scoring double in the first inning, put a big punctuation mark on the inning, sending his first career grand slam over the pool in right-center, leaving even the home fans a bit stunned.

“Hitting is contagious,” Pennington said. “It’s just one of those where guys get a couple of hits, you feel good, and things start to roll.”

After a shaky start to the season, Cahill had pitched well lately, but Saturday’s game got off to an ominous start.

Colorado scored a run in the first inning when Marte misplayed Arenado’s double in the left corner, and Cahill missed a throw from Trumbo at first to allow another run to come across.

Cahill was sharp after that, allowing three runs on four hits and struck out seven for his first win as a starter since last Sept. 21 at Colorado.

“Anytime if I’m pitching and the team wins, it’s a good day,” Cahill said. “It felt good.”

The Rockies pulled within a run on Arenado’s homer in the eighth inning, but his throw to home on Trumbo’s chopper in the bottom half sailed high for an error, allowing two runs to score.

Arizona poured it on from there, compounding Colorado’s mistakes by knocking the ball around the park.

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Peralta was called up June 1 and immediately started hitting. He hasn’t really stopped. The rookie has set a club record with 67 hits through his first 56 games and has had at least two hits 25 times. He also became the first Diamondbacks rookie with at least five RBIs in a game since Mark Reynolds on Aug. 30, 2007, at San Diego.

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De La Rosa had a couple of shaky moments early, giving up Peralta’s run-scoring double in the first inning and Trumbo’s homer in the third. The left-hander settled in after that, giving up four runs on six hits in six innings.

“He always goes out and puts us in positions to win games, and that is what I thought he did (Saturday night),” Weiss said.

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The Diamondbacks had eight hits in an inning eight other times, most recently May 28 in the first against San Diego. The nine runs tied for second-most in team history behind a 13-run inning against Pittsburgh in 2010.

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Rockies right fielder Michael Cuddyer, out since fracturing his shoulder June 5, went 1-for-3 with an RBI for rookie-level Grand Junction in his latest rehab game. He is 6-for-10 with three doubles and four RBIs in three rehab games.

Diamondbacks shortstop Chris Owings tested his bruised shoulder with 30 swings in the batting cage and is hoping to progress to a simulated game.

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Rockies lefty Franklin Morales, who will start the series final Sunday, has held left-handers to a .232 average.

Diamondbacks lefty Wade Miley, who will oppose Morales, had his worst start of the season his last time out, allowing 10 runs in 4 2/3 innings against Kansas City on Aug. 5.