PHOENIX -- After feeling a bit of a dead arm in his last outing, Josh Collmenter opted to forgo his normal between-starts bullpen session this week. It brought him back to life.

The Arizona right-hander struck out a season-high eight and gave up four singles and an unearned run in the Diamondbacks' 5-1 victory over the San Diego Padres on Friday at Chase Field.

"I'm sure it did (help)," Collmenter said. "Give the arm a little break. We've been going at it for quite a while now. August is usually the time if you are going to get fatigued, you start feeling it. I think it was just good to rest and be 100 percent going in."

Collmenter (9-7) had retired 15 in a row and entered the ninth inning with a two-hit shutout but was removed after giving up two singles. The Padres scored on a two-out passed ball by catcher Miguel Montero to break the shutout.

Montero hit a two-run homer to cap a three-run first inning to give Collmenter an early lead en route to his first victory since July 20.

Collmenter registered his normal 87-88 mph fastball velocity after topping out at 81-82 mph in his previous start, a 10-3 loss in Miami in which he gave up five runs in four innings.

"He was sluggish. You could see much difference tonight," Arizona manager Kirk Gibson said.

Collmenter did not walk a batter and went to a three-ball count on only one batter while coming within two outs of his second shutout of the season. His eight strikeouts tied a career high set in his rookie year of 2011.

"For me, a lot of times it is getting in counts where they have to swing at pitches outside the zone," Collmenter said of his strikeouts.

"If I can get ahead in the count and I am locating my fastball, my changeup and my curveball are that much better. I am able to throw those off the fastball. I was able to get some on the changeups and some on high fastballs. Usually, I am not going to get a whole lot."

Montero also doubled for the Diamondbacks (54-75), who broke a six-game losing streak. They had lost nine of their last 11.

Right-hander Odrisamer Despaigne (3-5) gave up five hits and four runs (three earned) in five innings for the Padres (59-68), who have lost four of their last five. Despaigne struck out four and walked one.

"The story was their guy," San Diego manager Bud Black said. "We couldn't solve him. He pitched a good game and we couldn't square any balls up. It is a sneaky fastball from a little different arm slot. It is coming down from an angle that is a little deceptive and has the good change."

Shortstop Alexi Amarista had two hits and scored on a Montero passed ball with two outs in the ninth inning.

Arizona right fielder David Peralta tripled with two outs in the first inning and scored on first baseman Mark Trumbo's infield single into the hole at shortstop for a 1-0 lead.

Montero hit the next pitch off the right-field foul pole for his 13th homer of the season and a 3-0 lead.

"The pitch to Montero was a good pitch. He is just a good hitter," Despaigne said through an interpreter.

Arizona third baseman Jake Lamb beat out an infield single and advanced on two groundouts before scoring on a fielding error by Padres second base Jedd Gyorko for a 4-0 lead. Lamb drove in a run on a forceout to make it 5-0 in the eighth inning.

Amarista and third baseman Yangervis Solarte had third-inning singles for San Diego, but Peralta threw out Amarista attempting to take third on Solarte's hit to end the inning.

NOTES: San Diego RHP Andrew Cashner is scheduled to be activated from the disabled list for a start Saturday in Arizona. Cashner has been on the disabled list since June 23 with shoulder soreness. ... The Diamondbacks did not score more than four runs in any of their previous 11 games, and they scored only 21 on a recent 10-game road trip in which they were 2-8. … Arizona OF A.J. Pollock (fractured hand) is scheduled to resume his rehab assignment at Triple-A Reno on Saturday after being shut down for six days with hand soreness. ... San Diego RHP Tyson Ross has made 12 straight quality starts, a franchise record, after giving up two runs in eight innings of a 2-1 loss to the Dodgers on Thursday. Six Padres, including RHP Gaylord Perry (1968-69) and RHP Andrew Cashner (2013-14), have made 11 straight. ... Arizona RHP Bradin Hagens was outrighted off the 40-man roster Thursday. Hagens was the club-record 18th rookie to appear for the D-backs this season when he made his first major league appearance Aug. 14.