THERE have been no takers among the top women's middle distance runners in the world for the challenge of stripping Sonia O'Sullivan of her unbeaten record in Nice this evening.

The composition of the field lining up with her in the 3,00() metres race is more noteworthy for those who are missing than for those who can expect to see only the back of the champion in the run to the finish.

Fernanda Ribeiro and Gabriela Szabo, two of those who will be expected to provide more resilient opposition in the 5,000 metres in Atlanta, have both decided against taking on O'Sullivan at this advanced stage of their preparations.

Missing, too, will be the reigning Olympic 1,500 metres champion, Hassiba Boulmerka, the great imponderable in the Olympic equation, who has raced only lightly this summer and goes over the shorter distance tonight.

Zonha Ouaziz, the Moroccan who finished third in the 5 000 metres behind O'Sullivan at the World Championships in Gothenburg, is a definite starter and others on the line will include Alison Wyeth (Britain), Gwen Griffiths (South Africa), Florence Borsosio (Kenya) and Maria Gruida of Italy.

On the face of it, it should turn out to be little more than a useful training run for Sullivan but before leaving London yesterday she was careful to guard against over confidence.

Every race produces a different challenge and while many of the big names are missing, the job of winning still has to be taken seriously," she said.

Also tonight, Linford Christie gets back on the gold trail after injury, but Britain's top 1,500 metres hope, Kelly Holmes, has been forced to curtail her buildup for Atlanta.

Christie, the 1992 Olympic gold medallist, takes on world champion Donovan Bailey over 100 metres in what will be the 23rd race of a hectic summer.

The 36-year-old Christie was forced to pull out of the lucrative Oslo meeting at the end of last week because of hamstring problems. Following treatment with a sports doctor in Germany, the Briton is fit again to run in France before a last pre-Olympic test at the Securicor Games at Crystal Palace on Friday.

But Holmes, the double world championships medallist has withdrawn from the 800 metres, the second time she has pulled out of a Grand Prix meeting this week. She missed the 1,500 metres in Stockholm on Monday night with sinusitis.

It means Holmes will have to make the "biggest decision" of her life without completing her planned racing schedule.

Holmes intended seeing how the two races went before settling on one or the other - or both - in Atlanta.

But a comprehensive 1,500m defeat in Oslo by O'Sullivan may have helped make up her mind anyway. Holmes will be watching Nice with particular interest when Boulmerka, the woman who beat her in the 1,500m in Gothenburg last summer, makes one of her rare appearances this season.

The Algerian will clash with in-form Carla Sacramento in the metric mile. The Portuguese defeated Mozambique's former 800 metres world champion Maria Mutola in Stockholm.

Meanwhile, Michael Johnson - denied the opportunity of running in London by the British Athletic Federation - returned to the United States after completing his Olympic preparation' with victory in the 200 metres at Stockholm.

"I am going home to rest and just keep my fitness up before the Games, and when I relax, I relax.... I don't do anything, said Johnson.

Johnson is attempting what would be an historic Olympia 200-400 metre double in Atlanta a feat no man has ever achieved.