SAN DIEGO (AP) -- Matt Kemp has played a big role for the Padres this year. But despite hitting a two-run homer on Monday, he was a big part of San Diego's 6-4 loss to the Colorado Rockies.

Kemp dropped a flyball for a key error and the Padres lost their fourth in a row and for the sixth time in seven games.

"He's done so many great things for us all year," Padres interim manager Pat Murphy said. "Matt Kemp has led us to many victories. He's been unbelievable. He doesn't usually drop that ball. We have to pick him up. That's what teams do."

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Charlie Blackmon and DJ LeMahieu opened the third inning for Colorado with singles and Nolan Arenado hit a double for a 3-2 lead.

Then Daniel Descalso hit a towering, two-out fly to right field and Kemp drifted near the base of the fence. The ball glanced off Kemp's glove for a three-base error, with LeMahieu and Arenado scoring.

The Padres had tied it at 2 on Kemp's home run. It was his 19th of the season and extended his streak of reaching base to a career-high 27 games.

But they couldn't overcome Kyle Kendrick pitching five innings and hitting his first major league home run.

"Was that his first?" a disgusted Ian Kennedy said. "He did a pretty good job of letting us know."

Kendrick (5-12) allowed three runs, seven hits and two walks as the Rockies won for the first time in seven games at Petco Park.

John Axford, the seventh Rockies pitcher, worked the ninth for his 20th save in 25 chances.

Arenado, tied with teammate Carlos Gonzalez for the NL lead in homers with 36, left in the eighth inning with a chest contusion. X-rays were negative and he was listed as day-to-day.

Arenado was injured diving into the stands attempting to catch a pop fly in the sixth inning.

Kennedy (8-13) pitched five innings and was charged with six runs -- four earned -- seven hits and a walk. He struck out nine.

"I feel like I was able to battle out of some innings with my fastball," Kennedy said. "But my changeup and breaking ball weren't that great."

The Padres cut their deficit to 6-4 in the sixth on a throwing error by catcher Dustin Garneau. San Diego had the go-ahead run aboard but Wil Myers struck out after just missing a grand slam with a drive that went just foul.

"From my vantage point it was going to be fair and then ... that really typifies what the game was about today," Murphy said. "Things just didn't go our way."

San Diego pulled within 6-3 in the fourth as Justin Upton walked and came around on Jedd Gyorko's double

Kendrick hit his home run in the fourth.

WEATHER OR NOT

The last time the Rockies were in San Diego on July 19, their game at Petco Park was rained out. When returning on Monday, they were greeted with weather more suited for a San Diego summer at 87 degrees. The rainout is being made up on Thursday.

TRAINER'S ROOM

Rockies: C Nick Hundley was out of the lineup with a sore neck. He is day-to-day.

Padres: RHP Joaquin Benoit was unavailable with a sore back.

UP NEXT

Rockies: RHP Jon Gray (0-0, 6.15) is seeking his first major league win; the Rockies are 1-5 in his starts. He had a no-decision when facing the Padres on Aug. 15, pitching five innings and allowing four hits and a run. He was leading 3-1 when he left.

Padres: RHP Colin Rea (2-2, 5.47) won his first two starts, but has lost his last two decisions. He had a no-decision in his previous outing, working five innings and giving up four hits and two runs against the Dodgers on Thursday. He had a career-high six strikeouts.