RIO DE JANEIRO (Reuters) - Jamaica's Deuce Carter advanced to the semi-finals of the Olympic 110m hurdles at the second attempt on Monday after he was allowed to take part in a re-run heat after rain played havoc with the competition.

Jamaica's Omar McLeod splashed through the puddles to win the first heat but compatriot Carter, completely thrown by running in rain for the first time, was disqualified from Heat 2 after hitting a hurdle and going out of his lane.

More rain eventually led to the suspension of the heats but not before the first two had been run in what McLeod described as "atrocious" conditions.

"I was trying my hardest to console him but he was really devastated," said McLeod, the gold medal favourite. "I can just imagine how he feels, it's his first Olympics and he had the ability to make the final. It's heartbreaking to be honest."

However, organisers decided that Carter and seven other athletes who failed to qualify by place from the first two heats would be allowed to run again in a heat after all the other scheduled races had been completed.

"This decision was taken to ensure fairness, because the conditions for heats one and two were dramatically different than the other heats," the IAAF said in a statement.

Carter duly won the re-run in 13.50 seconds, though he looked thoroughly miserable about the whole thing despite his unusual reprieve.

Given the technical nature of the event, it was perhaps not surprising that quite a few of the leading contenders were knocked off their stride by the wet conditions.

Dimitri Bascou of France and American Ronnie Ash had no problems and shared the second best time of 13.31sec to win their heats.

Devon Allen, second fastest in the world this year, only managed second place in his heat in 13.41sec, however.

Another likely medal contender, Spain's Orlando Ortega, won the wettest heat in 13.32sec, the fourth-fastest time of the evening.

Joao Vitor de Oliveira was one of two Brazilians to qualify after swallow-diving across the line in fourth place in Heat 3.

"I always do that. That is not an accident. I started doing it a long time ago," he said. "If I am in a fight I will always put myself first. I did it in China at the world championships and I broke my ribs.

"People tell me not to but I will do it. It comes from the heart. I am in my home Olympics."