DENVER — The Los Angeles Dodgers came into Coors Field fully anticipating a clinch. They leave a little clenched.
Being swept by a last-place team will do that.
The magic number for Los Angeles (87-68) remained at two after San Francisco (81-74) beat Oakland. The Dodgers open a four-game series against the defending World Series champion Giants on Monday at AT&T Park, where they are 0-6 this season.
"It's pretty embarrassing to come in here and get swept this late in the year," pitcher Alex Wood said. "If you look at the two teams today and don't know anything about baseball, I think you would've guessed the Rockies were about to head to the postseason and we weren't."
"We'll get a real big wakeup call here (in San Francisco)."
"Bet a lot of teams that would trade spots with us right now," Dodgers manager Don Mattingly said. "I like where we're at. I don't like we've lost three straight games. But at this point, you can't do anything about it."
Arenado hit his 41st homer in the fourth. He also had a sacrifice fly and a run-scoring single, giving him a major league-leading 126 RBIs this season.
"It means a lot (to sweep LA)," said Arenado, whose team finished 36-45 at Coors Field to avoid tying their worst home record, 35-46 in 2012. "We didn't quit. We're not quitting. We never have."
Chris Rusin (6-9) surrendered four runs — three earned — in 5 1/3 innings as Colorado swept Los Angeles for the first time since 2007.
Wood (11-12) couldn't hold a 4-1 lead, allowing eight runs in 5 1/3 innings. He limited Colorado to one hit over eight scoreless innings two weeks ago.
Arenado gave the Rockies the lead for good when he lined a fastball from Wood into left-center bleachers.
But it was a slide that set up Arenado's theatrics. DJ LeMahieu hit what looked like an inning-ending double play, only to have a hard-charging Charlie Blackmon cause second baseman Howie Kendrick to throw high and allow LeMahieu to beat the throw.
"This a tough time of year, honestly," Mattingly said. "It's tough to win games. It's tough to beat people. It's just tough."
Now, it's off to San Francisco.
"They're a good ballclub," Wood said. "I know the last thing on anybody's minds in the San Francisco's clubhouse is losing to us and letting us clinch on their field."
Mattingly wouldn't rule out Yasiel Puig (hamstring) from playing in the postseason — should the Dodgers qualify, of course — but acknowledged it may be difficult since the outfielder hasn't played in a month.
"Right now, it's not part of the equation," Mattingly said. "When it becomes part of the equation, then we can think about it a lot more."
Dodgers: 1B Adrian Gonzalez (pinched nerve) feels better but was kept out of the lineup as a precaution. Mattingly is hopeful Gonzalez can play Monday. ... INF Corey Seager didn't start because of heavy legs. He entered as a pinch hitter in the seventh and struck out. ... OF Kike Hernandez (hamstring) is expected to join the team in San Francisco.
Rockies: SS Cristhian Adames left the game after the second when he bruised his neck and right index finger on a collision with Joc Pederson while covering third base. Rafael Ynoa took his place and had an RBI double.
Dodgers: His sore calf feeling better, Greinke (18-3, 1.65) takes the mound Monday in San Francisco.
Rockies: RHP Christian Bergman (3-1, 4.62) starts Tuesday in Arizona. He has a 1.78 ERA in 10 road games — one start — this season.