Beijing, August 22

Usain Bolt and Justin Gatlin moved closer to setting up the biggest duel of the world championships, striding into the semi-finals of the 100m with victories in their heats on Saturday.

Gatlin upstaged the Jamaican with the top time in the first round, even though the American got a little push from nature with a strong back wind of 2.1 metres per second during his 9.83-second race. Bolt could count on an adoring crowd but faced a slight headwind as he cruised to a time of 9.96, the fifth fastest overall.

“It was OK. It was not perfect,” Bolt said. “I still have some adjustments. Just have to concentrate on my technique now.” Gatlin had no such complaints after his run. “I felt safe, like, after 50 metres so I did not have to push it too much,” said Gatlin, who was 0.13 seconds faster than Bolt. Those results will mean nothing by Sunday’s semi-finals and final, when the crowd at the Bird’s Nest will be hoping for a memorable head-to-head between the sport’s biggest star and the 33-year-old American who has not been beaten in two seasons after returning from a second doping ban.

Bolt has been struggling with injury and form during Gatlin’s comeback streak and on Saturday even his showboating was turned off. Beyond a few perfunctory waves and smiles, it was all business from the bearded Bolt. The flashiest part of his showing at the stadium where he won 100 gold with a world record seven years ago were his lemon-yellow coloured shoes.

Gatlin faced some scattered boos from fans but nothing like the hostile media reception he has had in several nations. He flaunted his form, though, looking left from the outside lane just past the midway mark and coasting from then on to set the top time. Bolt, who celebrated his 29th birthday on Friday, was slow out of the blocks but once he was fully upright he used his massive strides to make victory look easy.

Just as Bolt has dominated sprinting, so has Mo Farah reigned over long-distance racing. And the British runner underscored that with another gold medal in the 10,000 on Saturday. However much the front-running Kenyans were seeking to dull his finishing kick with a punishing early pace, Farah never wavered. Even a trip and slight stumble as he was passing lapped runners with 350 metres to go could not deter him.

Farah finished in 27 minutes, 1.13sec in the sweltering heat of the Bird’s Nest. Geoffrey Kipsang Kamworor took silver, 0.63 seconds behind, and Kenyan teammate Paul Tanui earned bronze. Victory left Farah halfway to his third long-distance double since winning two golds at the 2012 London Olympics.

In the women’s shot put, the home fans were looking for a first gold medal for China. But Christina Schwanitz of Germany reduced Gong Lijiao to second place with a throw of 20.37m, seven centimeters more than Gong. Michelle Carter of the US took bronze at 19.76.

In the morning session, 19-year-old Ghirmay Ghebreslassie became the youngest man to win the marathon at the world championships and the first world champion from Eritrea. Ghebreslassie finished in 2 hours, 12 minutes, 27 seconds, holding off Yemane Tsegay of Ethiopia by 40 seconds. Solomon Mutai of Uganda was third, while his teammate, defending world champion Stephen Kiprotich, was sixth.

The biggest surprise of all was the wipeout of the Kenyan team, which some favoured to get a sweep in Beijing. Instead, world-record holder Dennis Kimetto and Kenyan teammate Wilson Kipsang dropped out of the race, while Mark Korir finished 22nd.

Olympic champion Jessica Ennis-Hill held the lead in the heptathlon after four events with 4,005 points, 80 clear of British teammate Katarina Johnson-Thompson. Nadine Visser of the Netherlands was third overall with 3,871 points, and Brianne Theisen-Eaton of Canada, the top performer this year, was fourth with 3,865.