SAN DIEGO -- Outfielders Matt Kemp and Justin Upton homered for the first time as San Diego teammates and second baseman Jedd Groyko added a two-run homer Friday night as the Padres opened the second half of the season with a 4-2 win over the Colorado Rockies at Petco Park.

Kemp and Upton both connected in the first inning against left-handed Rockies starter Jorge De La Rosa to give the Padres a 3-0 lead. Upton added a solo homer in the eighth against right-hander Rafael Betancourt.

"That's the first time we've homered in the same game," Kemp said rhetorically after learning it took 91 games for the Padres' Nos. 3 and 4 hitters to connect in the same game.

"We have to do that more often."

"That game had a great feel to it," San Diego manager Pat Murphy said of the Padres' third straight win. "That's the way you get on a roll."

The Padres wasted no time getting to De La Rosa, who is 0-3 in three starts against San Diego this season with a 9.00 ERA.

Kemp lined a 0-and-1 pitch from De La Rosa 401 feet into the second deck in left. For Kemp, a strong second-half hitter, it was his third homer in five games, his fifth in 17 games and his eighth in 33 games. His ninth homer of the season was only his third as a Padre at Petco Park.

Kemp has a history of success against De La Rosa. Kemp, who later drew a walk and doubled, is 20-for-46 against De La Rosa with four homers.

After Upton reached first on catcher's interference by Michael McKenry, Gyorko cleared the wall in center with a 417-foot drive, his second homer since being recalled from Triple-A El Paso on July 1.

"Everything went wrong in the first inning," said De La Rosa, who fell to 6-4. "Those pitches they hit were mistakes. We lost the game right there. It was really frustrating. I threw much better after the first, but those mistakes ... it was a rough game for me."

Meanwhile, Padres right-handed starter James Shields also struggled, although he ended a three-game losing streak by picking up his first win since going to 7-0 on June 3.

Shields allowed one run, seven hits and four walks with six strikeouts in five innings. Only 56 percent of the 100 pitches he threw went for strikes.

The Rockies had Shields in continuous trouble but didn't get on the scoreboard until center fielder Charlie Blackmon led off the fifth with his 12th homer of the season and his fourth against the Padres.

The Rockies stranded at least one runner in each of the five innings worked by Shields with a total of seven left on base, including four in scoring position and three at third. The Padres also turned a double play and two Rockies were nailed on the bases.

"I didn't have my best stuff, but I made pitches when I needed to," Shields said. "I kind of leaned on everything ... I had to grind it out because I wasn't locating."

Right-handed closer Craig Kimbrel picked up his 24th save in 25 chances with a perfect ninth after right-hander Joaquin Benoit worked a perfect eighth.

The Rockies had cut the deficit to 3-2 in the seventh with an unearned run against Brandon Maurer. Brandon Barnes scored from third on a throwing error by Padres catcher Derek Norris.

Upton's 15th homer of the season was a 413-foot shot to left that, like Kemp's first-inning liner, reached the second deck.

The key play of the game might have come on Shields' final throw in the fifth -- which went to third rather than to the plate.

With runners on first and third and two out with one run already in, Shields threw to third in an attempt to pick off Rockies shortstop Troy Tulowitzki. But Padres third baseman Yangervis Solarte quickly came off the tag and trapped Ben Paulson as he tried to advance to second. The first baseman was tagged out in a rundown and Tulowitzki was unable to score.

NOTES: LHP Cory Luebke, who has had two rounds of "Tommy John" surgery since he last pitched in the major leagues early in the 2012 season, had his latest comeback attempt aborted Thursday when he had surgery to reroute a nerve in the elbow. He is expected to be sidelined four to six weeks. ... Rockies OF Corey Dickerson, who has been on the disabled list since June 17 with plantar fasciitis in his left foot, could start a rehab assignment next week if he responds favorably to physical tests the next couple days in San Diego. ... The Rockies have yet to name a starting pitcher for Sunday's game. ... SS Troy Tulowitzki drew two walks and singled Friday to stretch his run of reaching base to 39 games, the fourth-longest streak in franchise history.