At about 7 p.m. Saturday, 25-year-old Mario Gutierrez was escorted by a group of handlers and several police officers into the paddock at Churchill Downs.

The sign over his head, the one touting the 138 years of Kentucky Derby history by listing the first and last winners, had already been changed to add: I’ll Have Another.

Gutierrez became the 42nd jockey to win in his first try at the Derby, guiding the long-striding, Doug O’Neill-trained colt past 4-1 morning line favorite Bodemeister in the final furlong to a victory by 11 / 2 lengths.

Originally a 15-1 choice, I’ll Have Another became the first horse to win from the No. 19 post position and paid $32.60, $13.80 and $9.

Bodemeister was second and returned $6.20 and $5.60.

Dullahan, trained by Preakness winner Dale Romans, was a neck back in third and paid $7.20 to show.

“He’s such a professional horse,” Gutierrez said of I’ll Have Another, a chestnut colt purchased for $35,000 as a 2-year-old. “He’s a really calm horse. He gives 100 percent every time, as soon as you ask him.”

Gutierrez watched the Derby last year from the jockey’s room at the Hastings track in Vancouver. Then he won the 5th, a claiming race for fillies and mares with a purse of $26,000 (Canadian) aboard Caged Mistress.

The Kentucky Derby has a guaranteed purse of $2 million.

“Like all jockeys, we all dream that one day, fortunately, I would be in the Kentucky Derby,” he said. “All that time I was at Hastings Park and of course like a joke I had the dream, but I wasn’t thinking it was going to be the next year.”

Bodemeister lived up to his reputation as the fastest horse in the race. He broke to the front and forced a daring pace on a warm, humid day. I’ll Have Another hung back, moving toward space in the final turn before breaking from a pack and making up at least a five-length gap to overtake Bodemeister.

“At the top of the stretch, I really thought we had it,” Bodemeister jockey Mike Smith said. “But I knew we were in trouble when I saw Doug’s horse coming.”

Owned by California-based owner J. Paul Reddam, I’ll Have Another won the Santa Anita Derby but had gone overlooked most of the week. O’Neill blamed that on the inexperience of the trainer — he’d saddled only two Derby horses before, both in 2007 — and jockey.

On Cinco de Mayo, the Mexican-born Gutierrez said he’d felt that reporters thought he would break under the pressure.

“This is a great opportunity in my life,” he said. “I wasn’t going to come here and melt down, that’s for sure.”

O’Neill, the burly, jovial, bearded Midwesterner, bounded onto the track after the win and delivered bear hugs, often to people who weren’t looking. He immediately pointed the horse toward the second leg of the Triple Crown.

“We’re going to the Preakness, baby!” he said more than once. “We’re going to Maryland.”

O’Neill plans to keep I’ll Have Another at Churchill Downs until shipping to Pimlico. The horse’s connections hope he’s fresh enough to win the first Triple Crown since 1978, when Affirmed did it.

“We gave the horse only two preps this year,” Reddam said. “Part of the idea was we knew we had a good horse, and we wanted to make sure he was fresh, because the Triple Crown is a gamble and it looks like it paid off.”

Gutierrez ended up on the horse when O’Neill and Reddum decided to push I’ll Have Another directly into the Grade II Robert B. Lewis Stakes and figured they would not be able to hire a veteran jockey.

Gutierrez, new on the California circuit, had impressed them in a recent win.

By racing past Smith, a hall-of-famer who usually races in California, Gutierrez completed a meteoric rise.

But he also created a series of questions for trainer Bob Baffert, who said simply, “Wow,” as his horse’s sublime run went for naught.

“He ran his race,” Baffert said. “He was there and he just got tired a little bit. He’s only run four times.”

Bodemeister was trying to become the first horse to win the Derby after going unraced as a 2-year-old since 1882.

Second favorite Union Rags, trained by Michael Matz, had a poor trip and did not challenge.

“He broke a step slow and he usually breaks well from the gate,” jockey Julien Leparoux said. “Then he got bumped and we dropped far back. After the first turn and on the backside, I tried to find room inside but I had nowhere to go.”

I’ll Have Another — a popular horse among the many imbibers among the record crowd of 165,307 — found that room.

Afterward, his owner was asked if he had other goals.

“I don’t know how, at this point, anything could be bigger than the Kentucky Derby,” Reddam said. “If you hear of something, let me know.”

The people of Baltimore — and horse racing fans everywhere — probably have at least one suggestion.