ARCADIA — Bob Baffert’s unmatched experience at judging Kentucky Derby prospects has taught the Hall of Fame trainer that no matter what a young horse shows in his first race, he reveals more in his second.

“That’s when you know,” Baffert said in the Santa Anita winner’s circle.

After 3-year-old Barnes’ second race, Baffert knows he has another potential star in his barn.

Barnes and jockey Juan Hernandez dominated a small but solid field in the $200,000, Grade II San Vicente Stakes on Saturday, passing front-runner McKinzie Street on the turn for home and powering away to a 5½-length victory in a fast time.

Romanesque, the other Baffert-trained horse in the contest, finished second. Bullard, the morning-line favorite and narrow second choice of the bettors, was another half-length back in third. Smooth Cruisein was fourth and McKinzie Street faded to last.

Barnes paid $4 for a $2 win bet. The time for 7 furlongs was 1:22.15, best in six years in the San Vicente.

Baffert horses also ran 1-2 in the afternoon’s other stakes, with Richi ($8) and jockey Kazushi Kimura taking a rail trip to an upset over odds-on favorite Pleasant and Hernandez in the $100,000 Las Flores Stakes for filly-and-mare sprinters.

Baffert finished the day with four wins and Hernandez five, their other combined victories coming when 4-year-old Mirahmadi ($6.80) knocked off Eagles Flight in an allowance-level mile and 3-year-old Rodriguez ($3) romped in a maiden mile.

But the star of the day was Barnes.

As a son of leading American stallion Into Mischief (and the mare All American Dream) who cost owner Amr Zedan $3.2 million at a Saratoga yearling auction, Barnes had gone into his racing debut Nov. 27 at Churchill Downs in Kentucky amid high expectations.

He lived up to them barely, running greenly under jockey Martin Garcia and having to battle to win the 5½-furlong race by a head over Innovator. Nothing wrong with winning, but Barnes had room to improve.

He improved while making the big jump from maiden to graded-stakes class. Credit the longer distance, nearly three months of workouts at Santa Anita, and the maturity that a horse of this age can gain in as short a span as seven weeks.

“He moved way up here mentally,” Baffert said. “That’s what you want to see.”

Barnes’ early success might mean a little more around Santa Anita’s barn 5 because he’s named for Jimmy Barnes, Baffert’s top assistant trainer.

“They surprised me (with the name), and I was honored,” Barnes said after Saturday’s race. “I was a little nervous, but it is working out well so far.”

Starting from post 2, Barnes pressured McKinzie Street from the outside through quarter-mile fractions of 22.65 and 45.10 seconds, a comfortable pace for horses like this. The winner took charge coming into the stretch.

“He was aggressive down the backside, but he’s still learning how to run,” Hernandez said. “I like him because, around the corner pole, he got off the bridle and was kind of looking around a little bit, but when I corrected him, he came back to me. I was really surprised how he finished today.”

This was Hernandez’s fourth consecutive win in the San Vicente, including the past two years with Baffert-trained Havnameltdown and Muth.

It was Baffert’s 14th San Vicente win in 29 years. The first of those came with Silver Charm in 1997, a step toward Silver Charm giving Baffert the first of his seven Kentucky Derby victories.