DENVER -- The San Diego Padres erupted for three runs in the ninth inning Saturday night, taking advantage of Colorado's shaky bullpen and rallying for a 7-5 victory over the Rockies.

Rockies closer Tommy Kahnle blew his first save after converting his first two ninth-inning opportunities last weekend. San Diego scored six of its runs against the Colorado bullpen after Jon Gray, making his third career start, held the Padres to four hits and one run in five innings.

There was an unusual incident in the Padres' dugout in the eighth when left fielder Justin Upton slammed his helmet to the dugout floor after a running blunder, and the helmet bounced up and hit first baseman Yonder Alonso in the right temple. Alonso, who was checked out by a Rockies team doctor, did not have concussionlike symptoms and will be re-evaluated Sunday.

Padres catcher Derek Norris greeted Kahnle (0-1) in the ninth with a double into the left-field corner. Norris took third as pinch-hitter Cory Spangenberg bunted to Kahnle for a hit. Spangenberg was initially ruled out, but the call was overturned.

Center fielder Melvin Upton Jr. tapped a ball in front of the plate and catcher Nick Hundley glanced toward third base and then threw beyond first base, enabling Norris to score, Spangenberg to reach third and Upton to reach second.

"That's a play you need to make 100 percent of the time," Hundley said. "There's no excuse for that ... I rushed the throw, obviously made a poor throw, and it cost us the game."

Pinch-hitter Brett Wallace lined a first-pitch single to give the Padres the lead and third baseman Yergervis Solarte followed with a sacrifice fly that gave San Diego a two-run cushion. Wallace is 7-for-26 (.269) with one homer and five RBIs as a pinch hitter.

Wallace hit a fastball away and said he was simply trying to get the ball in the air with runners in scoring position.

"It's a pretty good position to come into," Wallace said. "You have guys in scoring position, makes your job a little bit easier, and it's a little bit more of rhythm to the inning. You're not trying to create something from nothing."

The loss was the Rockies' sixth straight and 13th in their past 17 games. In their six straight defeats, Colorado's bullpen is 0-2 with four blown saves and a 12.18 ERA (17 innings, 23 earned runs) and 24 hits allowed, including three homers.

The Padres have won four of their past five. They clinched their first series win at Coors Field since June 29-July 1, 2012, and won their first series on the road against a National League West opponent since June 23-25, 2014, at San Francisco.

Padres closer Craig Kimbrel posted his 33rd save, preserving the win for Kevin Quackenbush (2-1).

Gray gave up a run in the first on consecutive singles to start the game and right fielder Matt Kemp's sacrifice fly. Gray, who is on a pitch count of about 75 and an innings limit, retired 14 of the final 16 batters he faced.

"I'm learning quite a bit," Gray said, "but I'd say the biggest thing is to stay poised out there and try not to show emotion. If I make a bad pitch, I'm not showing emotion and executing pitches and it's working out so far.

"I felt really strong -- felt stronger as it was going on."

After hitting a one-out double in the eighth with the Padres trailing 5-4, Justin Upton was caught off second base by pitcher John Axford and tagged out in a rundown that went 1-5-4-1. A disgusted Upton then slammed his helmet, which bounced up and hit Alonso.

"We're out there competing, and that's a big point in the game and I made a big mistake," Upton said. "I was pretty upset about it. It's childish, man. I got to do better than that."

Upton apologized to Alonso, who said, "I was just watching the game and felt like something hit me across the head. It's part of the game. Guys get upset. I'm fine. Luckily everything checked out well and I can move on.

"I have a hard head, I guess."

NOTES: Rockies RHP Tyler Chatwood felt fine after throwing 15 pitches to hitters, the first time he has done that since undergoing his second Tommy John surgery July 24, 2014. ... Padres RF Matt Kemp's cycle Friday night was the second by an opposing player this year at Coors Field. Texas' Shin-Soo Choo accomplished the feat July 21. Kemp's cycle was the 14th in the history of Coors Field, which opened in 1995, and the seventh by an opposing player. ... Entering Saturday, the Padres had won 76 straight games, including 45 this season, when leading after eight innings -- the longest streak in the National League. ... Rockies LHP Tyler Matzek, a member of Colorado's Opening Day rotation, pitched in a game Friday for the first time since June 24 at short-season Class A Boise. Hindered by extreme wildness this season, Matzek threw 30 pitches (13 strikes) in one scoreless inning for Triple-A Albuquerque. He walked three and struck out two. ... Rockies 2B DJ LeMahieu tied his career high with his 18th stolen base.