BEIJING (AFP) - Athletics will seek to bury the sordid spectre of doping when it gets under way at the Beijing Olympics on Friday, with bitter rivalries in many disciplines guaranteeing a feast of top-class sport. There is a raft of big-name draw cards and record-breakers for whom the stage is set to shine in one of the Games' blue riband events. This comes as a welcome relief for track and field organisers who have been plagued by negative doping stories in the lead-up to the Games. Friday's action gets off to a cracking start, with the three fastest men in history - Tyson Gay, Usain Bolt and Asafa Powell - racing the heats of the men's 100m sprint, with the final on Saturday. American defending champion Justin Gatlin will not be among the athletes lining up after failing in his bid to overturn a ban for testing positive in a drugs test. But Gatlin's sorry tale is soon forgotten when one sees the mouth-watering line-up on offer. American double world sprint champion Gay will go head-to-head with the Jamaican duo of Powell and Bolt, the past and current world record holders. Bolt surprised everyone by breaking the 100m world record set by Powell, the 21-year-old running 9.72sec in New York on May 31. Powell rebounded to beat Bolt in last month's meet in Stockholm - their last before the Olympics - but it is the world record holder who comes in as favourite to become the first Jamaican to win the Olympic crown. "I'm not worried," said Bolt, who will be going for a sprint double. "I'm in good form and for the moment everything is going well." Another crowd-drawing race will be the men's 110m hurdles. China will have defending Olympic champion Liu Xiang in the line-up, still smarting from losing his world record to Cuban rival Dayron Robles, who shaved one-hundredth off the previous record in clocking 12.87sec. Liu, also reigning world champion after winning in Osaka last year, will be bearing the hopes and expectations of 1.3 billion compatriots when he competes in the National Stadium known as the Bird's Nest, but he has expressed confidence that he will thrive. "He is a natural born hurdler and a terrifying opponent," Liu said of Robles. "But I still believe I can beat him, I am at that level now. "He (Robles) is younger than me and I have had the experience of the Athens Olympics. "The Olympics and other events are not the same. Including the final, you have four races in the Olympics and I know how to get the best out of myself during this process." The middle-distance running events look sure to be dominated by Ethiopians, notably Kenenisa Bekele and Tirunesh Dibaba, who go into the Games at the height of their form and at the top of their disciplines. Bekele, the 2004 Olympic champion and triple world champion over 10,000m who also won a silver over 5,000m in the Athens Games and holds the world records in both events, snagged an unprecedented sixth world cross title this season. He will be going for the double, but one rival in the 10km race will be compatriot Haile Gebrselassie. The former four-time world champion and double Olympic champion over 10,000m, who is the world record holder in the marathon but suffers asthma, has shunned the longer distance event over fears about the pollution and heat. Competing at Hengelo in May, Gebrselassie recorded a time of 26:51.20, the second fastest of the year over 10,000m. One of Friday's gold medal events will be the women's 10,000m, where three-time world champion Tirunesh Dibaba, her elder sister and 2004 Olympic runner-up Ejegayehu Dibaba and Mestawet Tufa could give Ethiopia a medal sweep. The younger Dibaba won the world cross-country title in March in Edinburgh and in June set a 5,000m world record. Her sister has settled for second in two races against her this season. Tufa has Ethiopia's fastest time this season at 30min 38.33sec in June although the year's top time belongs to American Shalane Flanagan at 30:34.49 with Kim Smith also a threat after a New Zealand national record effort of 30:35.54. Tirunesh Dibaba's bid for a doublecould be scuppered by arch-rival and team-mate Meseret Defar, the reigning Olympic and world champion in the 5,000 metres and triple world indoor champion in the 3,000m, who has come to Beijing determined to tip the scales in her favour. Defar saw Dibaba smash her world record over 5,000m this season at the Bislett Games in Oslo, but the 24-year-old fired back in Stockholm with a time just one second slower than the new mark. "Those who thought I had disappeared should watch my performance in Stockholm," said Defar, who has a 13-9 lead in head-to-head races with Dibaba. The other gold medal event on Friday is the men's shot-putt. The latter sees world champion Reese Hoffa, two-time Olympic runner-up Adam Nelson and world indoor champion Christian Cantwell giving the United States hope of a podium sweep. "I think it's very realistic," Hoffa said of a US 1-2-3. "Adam is a wily old veteran so he probably won't have any problems. I'll be intrigued to see what Christian does. He could be the guy who wins the Olympics because he's so powerful."