EDMONTON, Canada -- Maurice Greene starts the bid for a 100- meter world championship title hat trick on Saturday in what is also the farewell show of 1996 Olympic Champion Donovan Bailey in front of a home crowd.

The 100m heats and second round races are expected to tower over the day's two medal events, the men's shot put and 20 kilometers walk.

"I am here and ready to run," the three-time 1999 gold medallist Greene said on Thursday.

Greene, 27, is rated top favorite although he is suffering from Tendinitis in his left knee which may force him to skip the 200m race.

"I will decide on that after the 100m," he said.

Stiff opposition is expected from fellow American Tim Montgomery, who ran the fastest 2001 time of 9.84 seconds in perfect conditions four weeks ago in Oslo. Greene's teammate Ato Boldon of Trinidad and Tobago is second with 9.88, Greene's mark stands at 9.90 seconds.

Bailey is the sentimental favorite at the end of his career highlighted by the 1995 world title and 1996 Olympic gold in a then world record 9.84 seconds.

"The only reason I came back is because the worlds are in Canada. I have nothing to prove," said the 33-year-old who has been plagued in injuries in the past years.

The Walkers, meanwhile, will have to deal with stiff rules approved only on Wednesday by the IAAF congress in the wake of unfortunate events at the Sydney games, DPA reported.

From now on the chief walking judge has the power to disqualify any athlete who has infringed the rules in the final part of the race when the Walkers leave the circuit for the stadium and on the track in the stadium to the finish - regardless if they received earlier warnings or not.

At the Olympics last year, the initial 20km winner Bernardo Segura was disqualified after the race and three leaders were disqualified in the women's 20km, including Aussie Jane Saville as she was about to enter the stadium.

Saturday's walk will see neither Segura nor defending champion Ilya Markov of Russia, while the 20km and 50km Sydney gold medallist Robert Korzeniowski of Poland will only compete over the long distance.

Compatriot Dimitri Jesipchuk has the best time of the year and Belarussian Victor Burayev won the European Cup.

The men's shot put also takes place without the defending champion as C.J. Hunter of the U.S. is banned for Nandrolone doping.

There will be two questions around the final - who will beat the 21m mark after an inconsistent season by many; and can U.S. veteran John Godina add a third title after earlier success in 1995 and 1997.

Godina is currently the number 2 in the 2001 list with 21.95m, close behind South African Janus Robberts who has 21.97m. The only other man over 21m this year is Spain's Manuel Martinez (21.29m) as Olympic Champion Arsi Harju of Finland managed only 20.98m.

Saturday's action will also see Pole Vault world record holder Stacy Dragila of the U.S. in qualifying action. The women's Heptathlon kicks off with Olympic champion Denies Lewis possibly sidelined with injury.