Kamworor overcomes wind and wet Cardiff, plus a fall at the start to defend title, by Cathal Dennehy

For Geoffrey Kamworor, it couldn't have started any worse, but after a 13.1-mile exhibition on the streets of Cardiff this afternoon, it couldn't have finished any better.

The Kenyan obliterated the field - including home favourite Mo Farah - to retain his IAAF World Half Marathon title on the drenched streets of the Welsh capital, and most impressive of all, he did it after falling flat on his face the moment the gun fired.

His Kenyan teammate Bedan Karoki finished a distant second in 59:36, with Farah third in 59:59.

Peres Jechirchir, photo by Getty Images for IAAF

The women's race was won in much more competitive fashion by Kenya's Peres Jechirchir, who came home in 67:31 to edge Cynthia Limo (67:34) and Mary Wacera Ngugi (67:54).

With Farah's camp talking down his chances in the build-up to the men's event - pointing to a recent illness and his focus understandably being on the loftier targets later in the summer - it was Kamworor who many considered the favourite, but in the very first steps of his race, it almost fell to pieces.

Kamworor slipped on the start line in the opening strides, a mistake compounded by the fact that the race was being run in conjunction with a mass-participation event, and as he tried to rise he was bundled to the ground again. Eventually the 23-year-old rose to his feet, missing the white cap he was wearing, and he began to slice his way through the field over the opening mile until he recovered his place at the front.

Kamworor's task was made all the more difficult by a swift early pace, which saw the leaders pass 10km in a blistering 27:59. Just past the halfway point, the strain began to show on the face of Mo Farah, who started to lose contact as the Kenyan quartet kept the pressure on at the front.

In the final miles, during which a torrent of rain lashed down on the athletes, the class of Kamworor began to show, and the 22-year-old began to move away from Karoki. At the line, he threw his arms in the air, aware that he had laid down a significant marker - not to mention landed a major psychological blow to his chief rival - ahead of the Olympic Games later this year.

"It was really tough after that fall to catch up but I fought hard," said Kamworor. "I am very happy to win again. I will focus on the 10,000m in Rio, and I'm looking forward to it."

On the evidence of this run, he has every reason to be relishing the thought of challenging Farah on what in recent years has become the Briton's domain. Farah himself dug deep over the closing miles to claw his way onto the podium, taking third in 59:59 ahead of Ethiopia's Abayneh Ayele, who also ran 59:59.

"It would have been nice to come here and get the win but a better athlete won on the day," he said. "Those guys were strong and I couldn't keep with them, it was an incredible pace."

Soon after, it was down to two, with Kamworor and Karoki together at the front in what was almost a rerun of their duel at the World Cross Country last year, the pair passing 15km in 41:41.

The women's race proved a much tighter affair, with a large group of seven going through 10km together in 32:34. Entering the final miles, the contest had boiled down to a three-way Kenyan battle, between Peres Jechirchir, Cynthia Limo and Mary Wacera Ngugi.

Limo attacked and built a short lead inside the final mile, but Jechirchir closed up again quickly and launched her own burst entering the final bend, which was good enough to carry her to victory in 67:31. "The race was not bad," she said. "The course was good but I struggled a bit climbing the hill."

Kenya took victory with ease in the women's team event, their leading three athletes accumulating a total time of 3:22:59, giving them gold for the sixth time in eight editions of this event ahead of Ethiopia (3:26:29) and Japan (3:32:25).

In the men's team event, Kenya was expected to sweep to the title with ease, and the East African nation didn't disappoint, taking gold with a cumulative time of their top three of 2:58:58, well clear of runners up Ethiopia (3:01:16) and bronze medallists Eritrea (3:06:18).