Kenya and Ethiopia resume an intense if friendly rivalry in the men's marathon on the final day of the London Olympics on Sunday over a course featuring some of the city's most distinctive landmarks.
"Sometimes the Ethiopians are strong, sometimes the Kenyans," Haile Gebrselassie, the finest distance runner of the modern era, said on Friday.
"We understand each other, without Kenya there's no Ethiopia. We need each other."
Gebrselassie, 39, had hoped to conclude his career by running in Sunday's race but time and injury mean he can no longer run the times needed to qualify for a strong Ethiopian team.
He lost his world marathon record to Kenyan Patrick Makau in Berlin last September and said on Friday he would not be running in next year's Moscow world championships.
Underlining the strength of the Kenyan team, Makau was not selected for the Games. Kenya will be represented by twice world champion Abel Kirui, this year's winner of the London marathon Wilson Kipsang and last year's champion Emmanuel Mutai.
Kirui said this week he thought he could break the Olympic record of two hours six minutes 32 seconds set by Sammy Wanjiru in Beijing four years ago. Wanjiru, the only Kenyan to win the Olympic marathon, died last year when he leaped from the balcony of his house after his wife found him in bed with another woman.
On Friday, Mutai said times were not important in Olympics or world championships.
"We are prepared for any kind of weather," he said.
"You have to be prepared for any kind of weather here."
Kipsang said he was ready to tackle the course, which starts and finishes in the Mall near Buckingham Palace.
"It's a nice course and I have really prepared myself very well," he said.
London, which hosts the world's best annual big city marathon, played a significant role in a race inspired by Greek soldier Pheidippides who, according to legend, ran to Athens in 490 BC to deliver news of the Greek victory over the Persians at the Battle of Marathon.
Spiridon Louis won the marathon run over approximately 40 kms for Greece at the first modern Olympics staged in Athens in 1896 to the delight of the home crowd but the next two in Paris four years later and St Louis in 1904 were disorganised shambles.
At the 1908 London Games, the British royal family took an active interest, with the race starting in the grounds of Windsor Castle and finishing in front of the royal box in the White City stadium.
As a result, the now standard race length of 26 miles 385 yards (42.195 kms) was set, a distance which became firmly established after one of the most dramatic races in Olympic history.
Italian Dorando Pietri, dazed and disorientated on a stiflingly hot day, was helped across the line by officials after collapsing several times. Following a protest from the Americans, the gold medal was awarded to Johnny Hayes who had finished second.
Promoters, sensing their opportunity after the race attracted tremendous worldwide publicity, invited the pair to turn professional and they staged several rematches each time over the London distance which was formally established by the world governing body 16 years later.
"If you talk about the Olympics, you have to talk about the marathon," said Gebrselassie, who won consecutive 10,000 metres gold medals in 1996 and 2000 before moving up to the marathon.
"The marathon is very close to the Olympics historically."
Despite the African dominance in distance racing, with Kenyans winning all six big city marathons last year, they have not monopolised the Olympic race over the past 20 years.
But Gebrselassie pointed out that the intense heat and humidity at the 1996 Atlanta and 2004 Athens Games, won by South African Josiah Thugwane and Italian Stefano Baldini, respectively, did not suit the Kenyans and Ethiopians who live and train at high altitude.
"In Sydney 2000 it was a Ethiopian (Gezahegne Abera) and in Beijing 2008 (Wanjiru) it was a Kenyan," he said.