The Rockies matched their longest winning streak of the season, improved to 12-4 since the All-Star break and are within four games of the second NL wild-card spot.
"We know we have enough talent," De La Rosa said.
Said manager Walt Weiss: "Next thing in our sights, chase down that wild card."
Colorado won despite losing NL home run leader Trevor Story to a jammed left thumb. The rookie shortstop hurt it on a scrambling slide in the fourth, jarred it again moments later diving for a ball and exited early.
X-rays on Story were negative. Rockies trainer Keith Dugger said Story might benefit from a day out of the starting lineup, but didn't envision any serious problems.
"He's going to be sore," Weiss said.
On the day the Mets retired Hall of Fame catcher Mike Piazza's No. 31, the Mets tied their longest skid of the season with a fourth loss in a row. The 43-year-old Colon (9-6) faltered in his first start on three days' rest since 2005, and slugger Yoenis Cespedes left in midgame because of a nagging quad injury.
"What is it, four in a row? That's not going in the right direction," Mets manager Terry Collins said. "But, as I told them last night, if we win the next four, we can forget about it."
"Right now we got to win the next three here. That's the next goal is to come out tomorrow and play a good game. We've still got to come here every day and grind it out," he said.
Collins was ejected in the ninth after umpires overturned their original call and took away a home run from Wilmer Flores, ruling a fan reached over the wall and prevented left fielder David Dahl from making a catch.
"I was going to catch it," Dahl said.
DJ LeMahieu drove in three runs and Dahl hit his second homer since making his big league debut this week, helping the Rockies reach .500 for the first time since late May.
Colorado's push toward playoff position has been boosted by its 6-0 mark against the Mets. Last year, the Rockies were 0-7 against them.
De La Rosa (7-7) gave up two runs in six innings and was part of Colorado pitchers retiring the last 16 batters. He is 100-82 lifetime.
"He's kind of the poster boy for how you pitch and succeed at Coors Field," Weiss said.
Justin Ruggiano had an adventuresome time after signing with New York earlier in the day. Cut by Texas on Tuesday, the veteran major league joined the Mets when they put infielder Jose Reyes on the 15-day disabled list with a strained left ribcage.
Ruggiano got a hit, but also overran a ball in center field for an error and was thrown out stealing on a replay reversal. He also was involved in a play that tilted the game.
Colon held Colorado hitless until Nolan Arenado singled with one out in the fourth. Carlos Gonzalez followed with a drive to right-center and Ruggiano ran a long way and made a diving try on the warning track, only to have the ball glance off his glove for a double.
Story followed with an infield hit and when the throw to first got away, he tried to advance and was thrown out. Dahl then lined a two-run homer for a 3-2 lead.
Charlie Blackmon doubled twice and set up LeMahieu's two-run single in the fifth.
Rockies: OF Ryan Rayburn didn't start for the second straight day, but singled as a pinch-hitter in the ninth. His left knee was bruised Friday night when he was hit by a ball during batting practice.
Mets: Cespedes left after grounding out to end the fifth. He stepped gingerly leaving the batter's box and jogged down the line. Collins said the Mets will give days off if need be, hoping he can avoid the DL.
QUALITY AND QUANTITY
De La Rosa turned in the 19th quality start by a Colorado pitcher in July, tying the team record for a month set in June 2009.
Rockies: RHP Chad Bettis (9-6, 5.19) is 5-1 in his last nine starts. Colorado has supported him with nearly seven runs a game over that span.
Mets: RHP Noah Syndergaard (9-5, 2.45) is 1/3 in his past five starts. The All-Star won his only career start vs. the Rockies last year.
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