LOS ANGELES -- It no longer matters what the Los Angeles Dodgers try these days. They continue to be pushovers during a spectacular freefall.

Clayton Kershaw was asked to ride to the rescue Thursday, but he only became the latest Dodger to stumble awkwardly.

Nolan Arenado hit a three-run homer three batters into the game, and the Colorado Rockies rolled to a 9-1 victory in the opener of a four-game series.

The Dodgers still own the best record in baseball at 92-48, but they have dropped 12 of their past 13 games, and there appears to be no end in sight to their slide. Their lead in the National League West over the Arizona Diamondbacks -- 21 games two weeks ago -- is down to 10 games.

"We don't think that we're a bad team," Kershaw said. "We won that many games for a reason. We played that well for that long for a reason. We are a very good team and we know that, but we're not showing it right now, for sure."

Carlos Gonzalez had three hits for the Rockies, while Arenado, Mark Reynolds, Trevor Story, Jonathan Lucroy and Charlie Blackmon had two hits apiece. DJ LeMahieu extended his season-best hitting streak to 15 games with a first-inning double.

Jon Gray (7-4) limited Los Angeles to one run on four hits and two walks in six innings. He struck out three. Mike Dunn, Scott Oberg and Adam Ottavino concluded the rout with a scoreless inning apiece.

Colorado increased its lead for the second NL wild card to three games over the St. Louis Cardinals and the Milwaukee Brewers. And they made it look easy.

"We know how good he is. We know that wasn't one of his better starts, but he's still Clayton Kershaw," Arenado said. "Lucky enough, I was able to get a pitch to hit. He missed his spot, and I was able to take advantage of the missed spot."

Kershaw gave up hits to the first four Rockies batters, including Arenado's three-run shot. It was the first time in his career he surrendered hits to the first four batters, doing so in his second start since coming off the disabled list after recovering from a lower back strain.

The Rockies pushed the lead to 4-0 on a third-inning sacrifice fly from Lucroy.

"It's bad right now; there is no getting around that," Kershaw said. "When you compare it to the first half, or the first however many games we played, it's the stark opposite. If anything, it doesn't make this easier, but thankfully we did win so many games early so we have a little bit of a lead right now."

Kershaw (16-3) staggered to a 28-pitch first inning. He was at 55 pitches after two innings and had reached 86 when he was pulled after 3 2/3 innings. Kershaw showed his frustration when he slammed his glove into the back wall of the dugout.

He finished the night giving up four runs and six hits, striking out seven while walking three. It was only the third time in 23 starts that he had walked at least three batters in a game.

Roberts attributed the early exit to both his left-hander's struggles and the close proximity to Kershaw's DL stint.

"I think if you look at the first couple of innings, there was stress, and to try to get him to (keep going), to what end is there to just keep him out there?" Roberts said. "To start the fourth inning at 71 pitches, I felt good that he could potentially have a quick inning and feel good about that outing. As we got up to 85, 86 (pitches), I didn't want to push him any further."

Kershaw was trying to become the first Dodgers pitcher to open a season 17-2 since the team moved to Los Angeles.

The Rockies had stumbled to a 3-6 record on their just-completed homestand and were looking to get back on track against the struggling Dodgers.

After going more than a week without a home run, Arenado crushed his 31st on the first pitch from Kershaw. It have him 15 home runs on the road, to go along with 16 at home.

"I don't want to get all dramatic here, but you can make the argument that that was our biggest win of the year," Arenado said. "Just a big win, coming to L.A. after a tough loss last night (at home against the San Francisco Giants), getting in late and just winning like that. Jon Gray pitched a great game for us, and it was just a big win."

Top Dodgers pitching prospect Walker Buehler made his major league debut in the eighth inning and hit 100 mph on the stadium radar gun with his second career pitch. He gave up a single to Gonzalez, his first batter, but faced the minimum six batters over two scoreless innings thanks to a double play. He struck out two, including Blackmon looking.

"Obviously, it was a pretty cool experience," Buehler said. "I felt like I threw the ball well, but unfortunately it was in a loss, so it was a little mixed emotion. But it was a special night for me."

Chris Taylor and Bellinger each had two hits for Los Angeles.

NOTES: Rockies C Ryan Hanigan (left groin strain) was activated from the 10-day disabled list, while CF Ramiel Tapia was recalled from Triple-A Albuquerque. ... Dodgers 1B Adrian Gonzalez received an epidural shot on his ailing lower back and is expected to be out of action for a few days. ... Dodgers SS Corey Seager is expected to return to the starting lineup Friday after not starting since Aug. 27 because of a sore right elbow.