There was no mistaking the most unruly horse in Saturday’s 136th Preakness Stakes.

Addled by the pre-race ruckus at Pimlico Race Course, Shackleford, the huge chestnut colt with the striking blaze, didn’t want to be saddled and bucked instead.

And afterward, with the honorary black-eyed Susan blanket draped over the victor’s broad shoulders, Shackleford didn’t want to pose for photographs either, yanking his massive sweaty head in protest.

All Shackleford wanted to do was race. He did so furiously, dominating virtually start to finish to claim the $1 million Preakness Stakes by half a length and scuttle any hope of a Triple Crown winner this year.

Kentucky Derby winner Animal Kingdom, the only contender with a chance to end the sport’s 33-year wait for a horse to replicate Affirmed’s 1978 feat of sweeping the Derby, Preakness and Belmont Stakes, finished second, mounting a stirring charge down the stretch only to come up short.

Shackleford jockey Jesus Lopez Castanon points to the sky after crossing the finish line. (Jonathan Newton/WASHINGTON POST)

“It’s tough to come that close,” said Graham Motion, Animal Kingdom’s Maryland-based trainer, “but he ran a huge race.”

Finishing third was Astrology, co-owned by Maryland native George Bolton, who was among the nine horses in the field that didn’t compete in the May 7 Kentucky Derby.

“I’ve won some big races,” said Shackleford’s trainer, Dale Romans, “but none as exciting as that one.”

Installed at 12-to-1 odds, Shackleford covered the 13 / 16 miles in an unremarkable 1 minute 56.47 seconds and paid $27.20 to win.

The sun-drenched afternoon made for a fast track. And the glorious weather — with a presumed assist from a controversial marketing campaign built around an infield mascot named Kegasus (half horse, half beer-bellied man) — helped draw the sixth-largest crowd in Preakness history, 107,398, marking the first time attendance has topped 100,000 since track officials barred fans from carting in their own alcohol in 2009.

As the surprise victor of an unusually slow-paced Kentucky Derby, Animal Kingdom, who trains just an hour northeast of Baltimore at Fair Hill Training Center in Elkton, arrived at Pimlico as the 2-to-1 favorite to win the second leg of the Triple Crown.

But it was Shackleford, for all his pre-race balkiness, who bolted to a clean start from Post 5.

Shackleford wasn’t the only high-strung horse as post time neared. It took five men to load Dance City in his stall, pushing the beast as if he were a minivan stuck in a bank of snow.

Animal Kingdom was in trouble from the start. Pelted in the snout by clumps of dirt, he dropped to the rear, settling in 13th in the 14-horse field.

Flashpoint set a torrid pace over the first quarter-mile (22.69 seconds). It was so fast that it worried Romans; his colt, Shackleford, was on Flashpoint’s right flank, determined to match his rival stride for stride.

Shackleford’s early strength wasn’t surprising given that he led most of the Kentucky Derby before finishing fourth.

Flashpoint held a slim lead into the far turn. By then, the blistering pace slowed, which bottled up the field behind and served to solidify the front-runners’ command.

Astrology then challenged for the lead, but Shackleford fended him off and muscled past Flashpoint on his left.

“I was more concerned if he was going to hang on,” Romans said, “but he kind of pulled everyone else out of the race.”

In auto racing, a car that performs best when running out front is said to “like clean air.” And clean air is what Shackleford enjoyed as he rounded the turn for home, with no other competitors to obscure his vision or kick dirt in his flared nostrils. He looked as relaxed as he had looked agitated in the minutes before the bugler’s call to post.

Then, as Shackleford came down the stretch, his jockey, Jesus Castanon, realized that a horse was moving up on the outside. It was Animal Kingdom, cheered by delirious fans and bettors as jockey John Velazquez deftly sliced him through traffic.

“That was the only horse that was gonna come and try to get me,” Castanon said, aware it was Animal Kingdom.

Exhausted by the pace, Flashpoint faded, while Shackleford thundered on, hurtling his forelegs, neck and every pound of flesh toward the finish,

“Our horse likes to look a horse in the eye,” Romans said. “He set right off of [Flashpoint] all the way around there. And then Flashpoint gave in, and we took over the lead. I think it blew up his heart. He felt good about himself at that point.”

Said Castanon: “When I got to the top of the stretch, I knew I still had some horse. When I asked him to pick it up, I could feel my horse get bigger.”

And when Shackleford, named for a barrier island off North Carolina, stormed across the finish, Castanon pumped his right first, crossed himself and blew a kiss to heaven, sure that his late father was watching.

Shackleford’s $600,000 winner’s share of the purse was sweetened by a $550,000 bonus that kicked in because of his participation in a race earlier in the season at Florida’s Gulfstream Park, one of Pimlico’s sister tracks.

Dialed In, who was eligible for a record $5.5 million bonus if he won the race, came home fourth. Dance City was fifth.

Mucho Macho Man finished sixth, denying trainer Kathy Ritvo the distinction of becoming the first woman and first heart-transplant recipient to win a Triple Crown race.

Flashpoint, who ran so impressively in the early going, ended up 14th.