LOS ANGELES — Manny Ramirez unleashed his pent-up power in one electrifying swing that landed, fittingly, in Mannywood.

Ramirez’s tie-breaking pinch-hit grand slam in the sixth inning on his bobblehead night Wednesday sent the Los Angeles Dodgers to a 6-2 victory over Cincinnati, their 12th consecutive at home against the Reds.

‘‘It’s crazy,’’ he said.

He was kept out of the starting lineup for precautionary reasons with a sore left hand after being hit by a pitch a night earlier.

‘‘Just the way he was sort of stalking around the dugout, I could feel something would happen if he had the opportunity,’’ Dodgers manager Joe Torre said.

Did it ever.

It was Ramirez’s grandest moment since returning July 3 from a 50-game suspension for violating baseball’s drug rules. He’s batting .347 with four homers and 17 RBI in 16 games since coming back.

‘‘I guess Manny’s hand wasn’t as bad as we thought,’’ Reds manager Dusty Baker said. ‘‘It doesn’t get more dramatic than that — a grand slam on your own bobblehead night. That’s the stuff that I’d seen out of Barry Bonds and Hank Aaron.’’

Ramirez said his hand felt good, but that he planned to ice it after the game.

Fans at the sold-out game chanted ‘‘Manny! Manny!’’ as they saw him in the dugout putting on his batting helmet. The anticipation built as the Reds changed pitchers.

Without a single practice swing, Ramirez sent the first pitch from reliever Nick Masset into the Mannywood section of lower left field seats for his 21st career grand slam, giving Los Angeles a 6-2 lead and putting the crowd into a frenzy.

‘‘It reminded me how loud it got when we hit those four (consecutive) homers against San Diego,’’ catcher Russell Martin said, referring to a dramatic Dodgers win in 10 innings against San Diego in 2006.

It moved Ramirez into second on the career grand slam list, trailing only Lou Gehrig’s 23. It was his first grand slam since 2005.

‘‘It was one of the best moments in my career,’’ he said. ‘‘I’m just glad it happened in LA.’’

Ramirez had never seen Masset pitch before, let alone heard of him.

‘‘That’s pretty much the area I wanted to put the ball. It just didn’t sink the way it normally does,’’ Masset said. ‘‘I was just trying to jam him, get a ground ball and get out of the inning. I was basically trying to go at him with my best stuff and it didn’t work out.’’

Teammates shoved Ramirez onto the top step of the dugout, where he waved his cap to acknowledge a standing ovation for his 11th homer of the season and his first career pinch-hit homer.

‘‘He’s the magic man,’’ Martin said.

It was Ramirez’s first homer into the ‘‘Mannywood’’ section, which was resurrected after his suspension ended.

Ramirez’s exhilarating moment was the only souvenir for 6,000 fans who went home without a bobblehead, which were limited to the first 50,000.

‘‘I was just trying to get a good pitch to hit,’’ said Ramirez, who arrived at his locker and peeled off his Dodgers shirt and white pants to reveal street clothes.

‘‘Now can I go home?’’ he said, drawing laughter.

The Dodgers set the stage for Ramirez’s heroics with one out in the sixth. Bronson Arroyo (10-9) walked James Loney and Matt Kemp, then Martin singled hard to left to load the bases. Arroyo gave way to Masset, who warmed up as the crowd got worked up in anticipation of Ramirez’s at-bat.

‘‘I’m running around the bases amazed, just laughing. I was in awe,’’ Kemp said. ‘‘He’s amazing, man. I can’t really explain him. I’ve never seen somebody who can go up there, no warmups or nothing, and just go hit. I need at least a couple of swings.’’

The victory moved the NL West-leading Dodgers 27 games over .500 for the first time since the last day of the 1988 season, when they went on to win their most recent World Series championship.

Ramirez pinch-hit for Chad Billingsley (9-6), who allowed two runs and seven hits in six innings, struck out seven and walked one. The right-hander won for the first time in his last seven starts and is 1-2 in that stretch.

‘‘Just listening to the crowd when he went up, something good was going to happen,’’ Billingsley said. ‘‘I wasn’t expecting a home run, though. He’s one of the greatest hitters of all time. We got the win, that’s all that matters.’’

Arroyo gave up five runs and five hits in 5 1-3 innings, struck out eight and walked four.

Andre Ethier tied the game 1-1 in the bottom of the first with his 20th homer with two outs. Joey Votto’s RBI double down the right field line notched the Reds’ first run in the first.

Loney put the Dodgers ahead 2-1 in the fourth with an RBI triple that scored Ethier, who walked.

Billingsley battled his control in the sixth, when he gave up a wild pitch with two outs that tied the game 2-2.

NOTES: The last time the Dodgers had a 12-game home winning streak was 1958-59, when they beat Pittsburgh that many times in a row. … Cincinnati manager Dusty Baker said before the game he planned to snag a keepsake bobblehead for himself, adding that Ramirez has been kind to his 10-year-old son.

Reds’ boxscore

Wednesday’s Game

Dodgers 6, Reds 2

Cincinnati Los Angeles

ab r h bi ab r h bi

Dickrsn rf 4 1 1 0 Furcal ss 4 0 1 0

Taveras cf 3 1 1 0 Hudson 2b 4 0 0 0

Votto 1b 4 0 3 1 Ethier rf 3 2 1 1

BPhllps 2b 4 0 1 0 Blake 3b 4 0 0 0

L.Nix lf 4 0 0 0 Loney 1b 3 1 1 1

Encrncn 3b 3 0 0 0 Kemp cf 3 1 0 0

Masset p 0 0 0 0 RMartn c 3 1 1 0

Wethrs p 0 0 0 0 Blngsly p 2 0 0 0

Sutton ph 1 0 0 0 MRmrz ph 1 1 1 4

HrstnJr ss 3 0 1 0 Mota p 0 0 0 0

Hanign c 2 0 0 0 Loretta ph 1 0 0 0

Arroyo p 2 0 0 0 Broxtn p 0 0 0 0

ARosls 3b 1 0 0 0 Pierre lf 3 0 1 0

Totals 31 2 7 1 Totals 31 6 6 6

Cincinnati 100 001 000 — 2

Los Angeles 100 104 00x — 6

E—A.Rosales (3). DP—Los Angeles 1. LOB—Cincinnati 4, Los Angeles 5. 2B—Dickerson (12), Votto (15), Hairston Jr. (17). 3B—Loney (2). HR—Ethier (20), M.Ramirez (11). SB—Taveras (19), Votto (4). CS—Hairston Jr. (3). S—Taveras.

IP H R ER BB SO

Cincinnati

Arroyo L,10-9 5 1-3 5 5 5 4 8

Masset 1 2-3 1 1 1 0 1

Weathers 1 0 0 0 0 1

Los Angeles

Billingsley W,10-5 6 7 2 2 1 7

Mota 2 0 0 0 0 0

Broxton 1 0 0 0 0 1

WP—Billingsley. Umpires—Home, Chris Guccione; First, Mike Winters; Second, Jerry Layne; Third, Tony Randazzo. T—2:46. A—56,000 (56,000).