De La Rosa gave up RBI doubles to Angel Pagan, Carlos Beltran and Daniel Murphy in the sixth and the Dodgers lost 5-2 on Monday night for their third straight defeat. They are a season-worst 12 games below .500.
"We got deflated in that inning and after that we didn't do much," manager Don Mattingly said. "We had a couple hits with guys in scoring position and from there, we weren't able to scratch anymore."
De La Rosa (3-4) gave up five hits and three runs over seven innings in his sixth career start, struck out five and walked a season-low one while losing his fourth straight outing. One of his victories came in relief.
"I didn't lose my concentration or my focus after the first hit," he said. "I was pitching the same. Everything was working for me. I thought I was attacking the zone aggressively, but in the sixth I was behind a lot in the count."
Andre Ethier was 0 for 4 with a strikeout and didn't hit a ball out of the infield, while Kemp was 1 for 2 with two walks, one intentional, for the last-place Dodgers, who dropped their third in a row and fifth in their last six. They fell a season-worst 12 games below .500.
"It's been tough, but we're grinding out every at-bat and every inning," second baseman Aaron Miles said. "We've played a whole bunch of close ballgames and we've been on the wrong side of more than we'd like to be, obviously. But nobody's giving up in here and nobody gets discouraged during the game."
Under Mattingly, the Dodgers have gotten more aggressive on the basepaths. They've been successful on nearly 80 percent of their stolen base attempts. Juan Uribe and Loney pulled off a double steal in the fourth, giving the Dodgers 11 steals in their last five games.
Chris Capuano (8-7) allowed six hits and two runs in six innings for the Mets. The left-hander struck out five and walked two in winning his third decision in a row.
"I didn't feel like I really had my best stuff out there, so it was kind of a grind," he said. "I'd been feeling like I was in a pretty good groove up until probably my last start and this start. Sometimes you get a little off with your mechanics and you just have to try to find what's working that day and try to go with it."
Francisco Rodriguez pitched the ninth to earn his 21st save in 24 chances.
Pagan was 2 for 5 with two runs scored hitting in Reyes' leadoff position. His RBI double keyed the Mets' comeback in the sixth and snapped an 0-for-11 skid.
"De La Rosa was pitching really well," Pagan said. "We were chasing some of his pitches close to the plate, but we were able to make the adjustment and win the ballgame."
After Capuano sacrificed Tejada to second, he scored on Pagan's RBI double to right field. The Mets tied the game at 2 on Beltran's double to right with two outs.
NOTES: The Dodgers purchased the contract of INF-OF Eugenio Velez and optioned SS Dee Gordon to Triple-A Albuquerque. ... In 16 starts, Capuano has yet to allow a run in the first inning, the only major league pitcher with a minimum of five starts to do so.