California Chrome's bid to complete US racing's elusive Triple Crown ended in disappointment when he finished fourth behind Tonalist in the Belmont Stakes on Saturday.             

Ridden by Mexican jockey Victor Espinoza, California Chrome moved into contention down the final stretch but could not sustain his run and catch the flying Tonalist (9-1), who won in a thrilling photo-finish.             

Commissioner, a 28-1 longshot, held on for second, beaten by just a head, after leading until the final turn while Medal Count (24-1) took third, a further length behind.

California Chrome (4-5 favourite) dead-heated with Wicked Strong (9-1) for fourth, sending the huge expectant crowd of more than 102,000 into a stunned silence at the realisation that the long wait for a Triple Crown winner would continue for at least another year.             

"Turning for home, I was just waiting to have the same kick like he always had before but today, he was just a little flat down the lane," said Espinoza.             

"I think it was tough for him. He ran back-to-back races in different tracks against all those fresh horses."             

Tonalist missed both the Kentucky Derby and the Preakness and showed the benefits of being fresh as he surged to victory in the 1 1/2-mile (2,400 metres) classic, the longest and most gruelling races of the Triple Crown series.             

"This is the Belmont, so this is great," said Tonalist's jockey Joel Rosario.             

"(But) I'm a little bit upset about California Chrome. If I was going to get beat, I wanted to just get beat by him."