DENVER -- The Colorado Rockies did their part Sunday to keep the Los Angeles Dodgers from celebrating a division title, completing a three-game series sweep with a 12-5 victory.

Third baseman Nolan Arenado hit a go-ahead, three-run homer, his 41st home run of the season, and had a career-high five RBIs, increasing his major-league-leading total to 126.

The Dodgers' magic number to clinch the National League West remained at two after the San Francisco Giants won at Oakland. The Dodgers open a four-game series on Monday at San Francisco with Zack Greinke and Clayton Kershaw lined up to pitch the first two games of the series.

"We're in a good spot," Dodgers manager Don Mattingly said. "There'd be a lot of teams that would trade spots with us right now. I like where we're at. I don't like the fact we lost three straight games."

The Rockies seemed headed for their worst home record ever in a full season after being swept in four games last week by Pittsburgh. But this series sweep enabled the Rockies, who are 66-90, to finish with a 36-45 home record, matching their home mark in 2012. The Rockies outscored the Dodgers 27-15 in the series.

"That shows you that nobody's signing off," right fielder Carlos Gonzalez said. "We continue to play hard. As long as there are fans in the stands, we got to play for them, because they pay for a ticket to watch a professional baseball team."

The Dodgers' inability to turn a double play cost them dearly in the fourth inning.

With one out and the bases loaded, Rockies second baseman DJ LeMahieu hit a grounder to third baseman Alex Guerrero. Rather than get the force out at home, he threw to second baseman Howie Kendrick, whose high throw pulled first baseman Scott Van Slyke off the bag.

"I think that's really what ends up hurting us, we're not able to convert that one," Mattingly said. "When that ball's hit, I think you're thinking two right away. It's a shot at two, get out of the inning. I think that's the right play."

Arenado, whose throwing error in the second allowed an unearned run to score, followed with a three-run homer off starter Alex Wood (11-12), connecting on a 3-2 fastball with two outs. Arenado, who hit a sacrifice fly in the three-run sixth and singled home a run in the three-run eighth, has 11 home runs and 31 RBIs this month.

"Obviously, I was (upset) about the error I made," Arenado said. "That throw was awful. I didn't set my feet, and I should've made a better play. I just tried to have a good at-bat. There's two outs, two strikes. I haven't had much success against Wood. I'm just trying to hit the ball hard, see it up. Luckily, I got a good pitch to do that."

Rockies starter Chris Rusin (6-9) worked 5 1/3 innings and left with a runner on first after throwing 100 pitches and getting nine outs on ground balls. Pinch-hitter Andre Ethier greeted reliever Gonzalez Germen with a single, putting runners on first and third.

Germen got shortstop Jimmy Rollins to fly to short left, but Kendrick was credited with a single to load the bases when his grounder clipped second base umpire Kerwin Danley on his foot. Germen then retired pinch-hitter Chase Utley on a fly to center.

The Rockies trailed 4-1 after Los Angeles' three-run third. The Dodgers loaded the bases with no outs and hit three weak grounders that netted three runs. The first was a tapper that Rusin fielded near the foul line. With his glove hand, he shoveled the ball home on a bounce, and catcher Tom Murphy was unable to secure it.

Rusin got two outs on ground balls, walked right fielder Chris Heisey to put runners on first and third and struck out center fielder Joc Pederson.

"He never gets flustered out there," Rockies manager Walt Weiss said of Rusin, who went 5-3 with two complete games in 11 starts this season at Coors Field. "Whenever a tough inning shows up, he fights his way through it. He knows how to minimize damage."

The Dodgers left 12 runners on base and went 4-for-20 with runners in scoring position.

"You got to score here, that's all there is to it," Mattingly said. "There's not many 3-2 and 4-3 games. Usually big innings come here and you just got to take advantage. If you don't, then you're in trouble."

NOTES: Rockies SS Cristhian Adames left the game in the second with a head and neck contusion as well as a right index finger contusion after getting tangled up with Joc Pederson on a play at third. ...Dodgers 1B Adrian Gonzalez, who has a pinched nerve in his lower back, was better, and manager Don Mattingly was hopeful he would be in the lineup on Monday. Gonzalez had a scheduled day off Sunday after being scratched from Saturday's lineup. ... OF Yasiel Puig (strained right hamstring), who is rehabbing at the Dodgers' training complex in Arizona, isn't yet playing in games and likely won't be ready for the first round of the playoffs. He has been on the disabled list since Aug. 28. ... Rockies SS Jose Reyes was not in the lineup for the fourth straight game and fifth time in six games due to left Achilles tendon soreness. ... Rockies LHP Yohan Flande will pitch out of the bullpen, if he returns, manager Walt Weiss said. He has yet to show he can run and field his position after suffering a left patellar tendon contusion when struck with a line drive Sept. 19.