By Nick Mulvenney
BEIJING (Reuters) - Britain's Mo Farah put a difficult few months behind him to retain his 10,000 meters title in some style as the opening day of the world championships finally shifted the focus from the doping crisis in athletics on Saturday.
Even with the superstars of the sport taking center stage on the first of nine days of action at the Bird's Nest Stadium, however, there were some reminders of the troubles that have engulfed the sport over the last three weeks.
A few boos spilled down from the stands when convicted doper Justin Gatlin was introduced ahead of his 100 meters heat, which he won with the fastest time of the day to take a confident step towards Sunday's highly anticipated showdown with Usain Bolt.
Farah's brilliant victory was achieved despite almost being tripped up on the last lap and also by the disruption to his preparations for Beijing following doping allegations leveled at his coach Alberto Salazar. Salazar denies any wrongdoing.
"It hasn't been an easy year," said the Olympic champion, who will go for an unprecedented back-to-back 5,000-10,000 meters world championship double next Saturday.
"As an athlete, I let my running do my talking. I've just got to keep doing what I'm good at and that is running and winning medals for my country."
Farah was almost tripped by Kenyan Geoffrey Kamworor as the leaders rounded the first turn after the bell but somehow stayed on his feet to deliver his trademark finish over the final straight and cross the line in 27 minutes 01.13 seconds.
"I nearly went down but I managed to stay on my feet and win the race," said Farah. "The (Kenyans) worked as a team, so hats off to them, they tried something different and they really made it hard for me."
It was Farah's sixth straight success in major championship distance finals since his second place in the 10,000m at the 2011 worlds in Daegu.
Jamaican Bolt's record since his triple Olympic sprint triumph in the Bird's Nest in 2008 has been even more impressive but he was served notice that he will have his work cut out to retain his world 100m title on Sunday.
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Gatlin underlined his dominance of the sprints this season by storming to victory in the sixth heat in 9.83 seconds before world record holder Bolt recorded the fifth best time to win his own heat in 9.96.
"If you look at Bolt, he did the same thing in 2012," said Gatlin, reflecting on his experience of winning bronze behind the Jamaican at the London Olympics.
"He ran kind of slow in the first round and the semi-finals then he triumphed in the final."
The International Association of Athletics Federations (IAAF) would have been hoping for athletic excellence to take the spotlight after weeks of embarrassing leaks and accusations that it has neglected its duty to root out drug cheats.
They got it in the first event of the championships when Eritrean teenager Ghirmay Ghebreselassie became the youngest ever marathon world champion with a stunning run in punishing humidity.
The second gold medal was won when Germany's Christina Schwanitz clinched the women's shot put title by just seven centimeters from China's Gong Lijiao.
"I must be one of the happiest people in the stadium," she said. "Seven centimeters, that's hard core!"
That result may have disappointed a healthy crowd at the venue for the 2008 Olympics but the few Kenyans in the crowd would have felt harder done by.
A silver and bronze behind Farah for Kamworor and Paul Tanui came after two of the African powerhouse's vaunted trio of marathon runners failed to finish and the other came home 22nd.
Ghebreselassie crossed the line in two hours, 12 minutes and 27 seconds to claim a first world championships gold medal for his country.
"My parents wanted me to be a great student but I wanted to be a great athlete," said the 19-year-old. "Today's victory will be a great surprise to them."
There was better news for Kenya in the 800m heats, where David Rudisha looked in good, if not dominating, form with a run of one minute 48.31 seconds to reach Sunday's semi-finals.
Another East African world record holder, Ethiopian Genzebe Dibaba, was in blistering form in the heats of the women's 1,500m, clocking four minutes 02.59 seconds for the fastest time ever in the first round at the world championships.
Britain looks like quickly building on Farah's golden start with Olympic champion Jessica Ennis-Hill and team mate Katarina Johnson-Thompson first and second after four of the seven events in the heptathlon.
(Additional reporting by Judy Hua, editing by Pritha Sarkar)