By David Martin, PA Sport

Zhanna Block will never forgot winning the world 100metres title in Edmonton two years ago - but now she faces a difficult task to retain her crown.

Spectators in Edmonton looked on in amazement as the Ukrainian thrashed defending champion Marion Jones in one of the biggest upsets ever.

This time around Block will feel the pressure of defending her crown in Paris - even though Jones will not be a threat.

The United States' Olympic champion will be in the French capital but after recently becoming a mother Jones, the partner of 100m world record holder Tim Montgomery, will be there as a spectator.

Block has been out of action since the Trikala Super Grand Prix meeting in mid-June, where she was surprisingly beaten by 1998 European champion Christine Arron of France.

"The reason I have been out is do to an injury to my quad muscle which has healed and I have been training very hard again for the past few weeks," said Block.

During her absence former Commonwealth champion Chandra Sturrup has dominated the 100m.

The Bahamian, along with Olympic 800m champion Maria Mutola, is in contention for the IAAF Golden Jackpot of a million dollars, after winning the first three Golden League meetings of the season.

Even with Jones absent, Block - who is also running the 200m - can expect an open race.

The 31-year-old, who has been training in an island off her Ukrainian homeland, can expect Sturrup to be her biggest threat, although US champion Kelli White, Arron, Greek champion Katerina Thanou and Debbie Ferguson will also be confident.

Despite her injury, Block's preparations have barely been interrupted. "I've only missed two days of training," said this year's world indoor 60m champion.