PHOENIX -- It was difficult for Colorado Rockies right fielder Carlos Gonzalez to rank his two game-turning plays Sunday.

Gonzalez's two-run homer in the sixth inning accounted for the final margin in the Rockies' 6-4 victory over the Arizona Diamondbacks at Chase Field, a lead that he preserved with a diving catch in the last of the ninth inning.

"They are both special," Gonzalez said. "The home run ended up being difference. The catch, they always feel good because I want to help my pitchers. In a big situation like that, it is just as special as a home run."

Shortstop Troy Tulowitzki's three-run homer in a four-run first inning gave Jorge De La Rosa (6-3) a big early cushion, and Gonzalez's homer gave the Rockies a 6-1 lead.

The Diamondbacks chipped behind right fielder Yasmany Tomas, who had a homer and three RBIs, and closed to within two runs in the eighth inning on doubles by center fielder A.J. Pollock and first baseman Paul Goldschmidt and a single by Tomas.

Pollock batted again with runners on first and second and one out in the ninth inning, and he hit a sinking line drive that three-time Gold Glove winner Gonzalez caught with a dive. Axford struck out All-Star starter Goldschmidt for the final out.

"There is no doubt in my mind that, off the bat, that's a hit," Colorado manager Walt Weiss said of Pollock's ball. "You're thinking, 'Here we go.' That's a big-time play by Cargo."

Axford had his 14th save in 15 attempts.

"They won the battle today," Arizona manager Chip Hale said. "That was a good job by Axford getting one of the best hitters in baseball."

Gonzalez had three hits and Tulowitzki had two, extending his hitting streak to a career-high 18 games. He also reached base for the 32nd straight game, another career best.

Tulowitzki's homer was the third of six straight hits against Arizona right-hander Rubby De La Rosa (6-4), who also surrendered Gonzalez's homer, his 11th of the season. It was an opposite field shot to left.

"I just followed the way he pitched me," Gonzalez said. "My second at-bat, he threw me a changeup away and I rolled over and hit a ground ball to second. He pitched the same on the third at-bat. The changeup comes up, and I was able to hit it the other way."

Jorge De La Rosa gave up two runs and five hits in six innings for his first victory in 10 career starts at Chase Field as the Rockies (35-47) salvaged the final game of a four-game series while winning for the second time in nine games.

"My first win here is nice," Jorge De La Rosa said. "I threw some good games here, but I never got lucky to win a game."

Tomas hit his fifth homer of the season in the second inning and had a sacrifice fly in the last of the sixth to cut Colorado's lead to 6-2.

Arizona (40-42) was unsuccessful in its 13th attempt to reach .500 for the first time since April 24, when it was 8-8. The Diamondbacks had won three in a row and five of their last seven.

Shortstop Nick Ahmed had three hits.

Center fielder Charlie Blackmon and second baseman DJ LeMahieu singled to open the first inning before Tulowitzki hit his ninth homer of the season. Gonzalez, catcher Michael McKenry and first baseman Ben Paulsen followed with singles for a 4-0 lead.

"If I can find my power stroke, it will definitely be brought into the game more than it has been," said Tulowitzki, who is hitting .321.

NOTES: Home plate umpire Fieldin Culbreth left the game after being struck in the chest by a foul ball with one out and two on in the last of the second inning. Jim Reynolds took over behind the plate in a three-man crew. ... Colorado 3B Nolan Arenado missed his third game of the season, his first since April 21. Arenado, a two-time Gold Glove winner who began the day with 24 homers and a major-league-leading 68 RBIs, committed three errors in the previous two games. ... Arizona LHP Patrick Corbin, who won his 2015 debut Saturday after recovering from Tommy John surgery, is scheduled to start again next Saturday, the second game of a three-game series at the New York Mets. Corbin's victory Saturday was his first since Sept. 11, 2013. ... Colorado LHP Jorge De La Rosa recorded his 1,000th major league strikeout when he got 1B Paul Goldschmidt swinging in the first inning. ... The game was the second matchup of starting pitchers named De La Rosa -- Colorado's Jorge and Arizona's Rubby -- in major league history. The first occurred when they faced each other June 25 at Coors Field.