The Louisiana Derby shaped up as more of a tactical race than a speedy one.

That didn’t matter to Steve Asmussen, trainer of Gun Runner — perhaps the most versatile horse in the field.

With jockey Florent Geroux aboard, Gun Runner took the rail early, came off it on the far turn and passed pace-setter Candy My Boy before pulling away down the stretch to win the $1 million Louisiana Derby by 4½ lengths Saturday at the Fair Grounds.

It was Gun Runner’s second consecutive victory, after taking the Risen Star on Feb. 20 — even though there were questions about whether Gun Runner, who picked up 100 points in the Kentucky Derby standings, could handle the Louisiana Derby’s 11?8-mile distance.

“He’s a very athletic horse,” Asmussen said. “I thought that he would be very handy. He’s got a very good temper to him, and I thought he stayed on to the wire at a mile and eighth very impressively today. He put in a lot of work on this track during the winter, and you see the results.”

Tom’s Ready, owned by Tom and Gayle Benson, was a surprising second, followed by Dazzling Gem. Favorite Mo Tom, the Bensons’ top Kentucky Derby hopeful, was a disappointing fourth, the worst finish of his seven-race career.

For the second consecutive race, Mo Tom, the 3-2 favorite, had a bad trip. In the Risen Star, another horse drifted in front of him, causing him to have to slow and be redirected. This time, he was held up behind horses.

Jockey Corey Lanerie blamed himself.

“He was running his race, and when I got to the 3/16ths pole, he took off,” Lanerie said. “I got to a wall of horses faster than I can navigate a trip cleanly. I just had too much horse than I knew what to do with, and I made decisions and got the horse beat. It’s a shame. He’s a good horse.”

Mo Tom’s recipe for success is to be held back, then make a big run in the stretch, passing tiring horses. Going into the race, Tom Amoss, Mo Tom’s trainer, was concerned about a slow speed resulting in pace-setters having enough energy to finish strong, and he was upset after the race.

“It was very similar to his trip in his last race,” said Amoss, an 11-time Fair Grounds leading trainer. “The rider made a decision to go down to the rail and, really, I don’t understand that decision. It doesn’t make any sense to me. It was a poor decision.”

With the Kentucky Derby on May 7, Amoss said he wasn’t thinking about it or making any changes yet.

“I just hope (Lanerie) didn’t hurt my horse,” he said. “I just want to make sure (Sunday) that my horse is OK. I’m just worried about my horse’s health right now. No decision will be made until after that.”

Lanerie was to ride another Amoss-trained horse, Our Lady Allie, in the 12th race, the Crescent City Oaks. Lanerie was replaced by veteran James Graham, and Our Lady Allie won.

Tom’s Ready’s trainer, Dallas Stewart, and jockey Brian Hernandez Jr. were ecstatic after their second-place finish. Tom’s Ready had a disastrous trip in finishing seventh in the Risen Star. But on Saturday, he gained 40 Kentucky Derby points; about 22 are needed for consideration.

“We still have some work to do with him,” Stewart said. “But coming off that bad race in the Risen Star, it was a big improvement. He fought off a foot issue after the Lecomte (on Jan. 16) and got through that in good shape. He’s healthy now and getting better.”

Geroux, who also rode Gun Runner in the Risen Star Stakes, said he is such a good horse because he “is very manageable and super athletic.” Gun Runner has shown he can run on the rail, in traffic or on the outside.

“You can put him exactly where you want to, and when you ask him to go, he always has that gear,” said Geroux, the Fair Grounds’ leading jockey. “This race was much better than the Risen Star because he is much fitter. He improved by a lot of lengths.”