According to a source, Farah remained unconscious for around three minutes, though he later made a full recovery and did not require hospital treatment.

The athlete later described his collapse as “not a big deal”, though his meltdown was a salutary reminder of the challenge he faces in translating his success on the track to the roads.

The post-race collapse capped a disastrous morning all round for Farah, who earlier in the race had been sent tumbling to the ground when one of his heels was clipped before the six-mile mark.

His fall was the cue for Geoffrey Mutai, a two-time winner of the full New York Marathon, to step on the throttle and within half a minute he and fellow Kenyan Stephen Sambu had opened up a sizeable gap on the rest of the field.

Farah quickly got back to back to his feet and set off in hot pursuit of the race leaders but he was already well adrift of Mutai by the time he got back into his running rhythm. By the nine-mile mark he was some 25 seconds behind.

Although he eventually overtook Sambu half a mile before the finish, he was never going to catch an athlete of the calibre of Mutai, who triumphed in 60min 50sec.

Farah finished second in 61min 18sec – well outside the British record of 60min 59sec he set in New Orleans a year ago – but the shocking scenes at the finish line showed how much it had taken out of him to try to get back into the race.

The fact that Farah felt well enough to talk to reporters within an hour of the race was proof that his condition was not too serious, though it not the preparation he would have wanted in his one and only warm-up race before he goes to the start-line.

“I do remember sort of passing out,” Farah said. “I tried so hard in the race, taking a fall and then going through. But, yeah, I’m all right. It’s fine. It’s not a big deal.”

In was his first competitive outing since he finished second in the Great North Run over the same half-marathon distance last September, Farah said he had no clear recollection about the tumble that effectively cost him the race.

“I’m not sure what happened,” he Farah said. “I just remember sort of falling down and just hitting the ground quite hard. I got caught on my hip, my ankle, the whole right-hand side.

“For the last four miles I struggled a bit. I was pretty much seeing stars.”

Farah, who has spent the last two months at high altitude in Kenya and is due to return there on Tuesday for his final pre-London tune-up, said the sub-zero temperatures in New York may also have contributed to his collapse.

“Conditions today were very cold,” said Farah. “London’s going to be different, but I felt good up to the point I went down. It happens in the race. You’ve just got to deal with it.

“It would have been nice to come out here and win the race but Mutai’s a strong athlete.”

Asked whether he would now be doing anything differently in the last few weeks before London, he said: “I guess nothing changes. You just have to continue training.”

Source: Telegraph