Kentucky Derby winner Real Quiet scored a three-length victory on Saturday in the second jewel of US flat racing's triple crown, the 123rd running of the Preakness Stakes at Pimlico racecourse.

Real Quiet, with Kent Desormeaux up, used the same move that won the Derby two weeks ago, coming four-wide around the clubhouse turn and blowing away the competition down the stretch to win in one minute 54.40 seconds.

The morning-line favourite, Real Quiet went off as the 5 to 2 second choice. Victory Gallop, runner-up to Real Quiet in the Derby, had to settle for second again under Gary Stevens. Classic Cat was third.

Real Quiet trainer Bob Baffert, who saddled Derby and Preakness winner Silver Charm last year, became the first trainer in history to condition back-to-back winners in the first two triple crown races. Baffert has trained the winners in four of the last five triple crown events.

"He's doing better than he was for the Derby," Baffert said. "When he came in here he wasn't that tired and he trained well with all the people around him. I think people will take him serious now."

Baquero, the D Wayne Lukas-trained speedster, led the field to the quarter-mile, with Black Cash and Basic Trainee in tow. The trio took the field to the half-mile in just over 46 seconds while battling temperatures above 90 degrees.

"I tried to take control of the race at the half-mile mark," Stevens said. "Real Quiet was outside and behind us most of the trip. I was able to make the move I wanted to but Kent was able to breeze by me when he wanted to."

"I nudged him a little bit and he went by them," Desormeaux said. "Right after that is was like where did they go?"

In the stretch, it was all Real Quiet. He pulled away, opening a big lead. At one point, Desormeaux even glanced back to check on the competition.

Victory Gallop was closer to the pack than in the Derby, when he came from out of nowhere to take second. Again, he was unable to run down Real Quiet before the wire.

"No match for the winner today," Stevens said. "No excuses for my horse. It was a gutty little horse I rode but Real Quiet just ran away from him."

Real Quiet won for the fourth time in 14 career starts and posted back-to-back victories for the first time in his career.

Real Quiet took home the winner's share of $650,000, but that would pale in comparison to the five million dollars bonus he would secure by winning the Belmont.

The last horse to win the triple crown - the Kentucky Derby, Preakness and Belmont Stakes - was Affirmed in 1978.

Affirmed was the third horse to do it in the 70s, after Seattle Slew in 1977 and Secretariat in 1973. Before that the gap stretched back to Citation in 1948.