NEW YORK (Reuters) - Ruler On Ice ploughed his way through the mud to score an upset win in the 143rd running of the $1 million Belmont Stakes Saturday after the Kentucky Derby winner Animal Kingdom almost threw his rider at the start. Perfectly ridden by Peru-born jockey Jose Valdivia, Ruler On Ice defied his generous odds of 24-1 to outstay his more favoured rivals to win the one and a half mile classic and claim the third jewel of American racing's Triple Crown after missing the first two legs. "With a half-mile remaining, I still felt like I had a lot of horse beneath me," Valdivia said. "Turning for home, everything started going in slow motion. At the sixteenth pole, I thought 'this is the true test of a champion.'" Stay Thirsty, another long shot, finished second by three quarters of a length after hugging the rail down the stretch while Brilliant Speed grabbed third, one and a half lengths behind the runner-up, after a late charge down the centre of a sloppy Belmont Park track. Animal Kingdom, which started favourite after winning last month's Kentucky Derby and finishing a close second in the Preakness Stakes, finished sixth after the colt blew his chances when he was bumped as the 12 runners charged out of the gates. John Velazquez was left clinging desperately to the reins after his foot was knocked out of the irons.