Sprinter Asafa Powell says rival Justin Gatlin does not want to race him.
Powell says Gatlin is "avoiding" him
"I cannot tell you where and when I'm going to meet Justin Gatlin on the track - it seems he's avoiding me," said the Jamaican.
His remarks come in the wake of doubts over a race in London on 28 July, the latest in a series of planned races between the 100m world record holders.
Powell races in the Paris leg of the IAAF Golden League on Saturday while Gatlin is nursing an injury.
The American withdrew from Monday's IAAF Super Grand Prix in Athens because of a strain in his leg.
Powell's last appearance at the Stade de France was three years ago, when he was disqualified in his World Championship quarter-final.
Since then he has become one of the finest sprinters around and refused to discount his chances of once again breaking the 100m world record, which stands at 9.77 seconds.
"I'm in good shape," said Powell. "I know anything is possible at this meeting. "My goal is simple; run fast from the start to the finish line."
Powell is in with a shout of the $1m jackpot as he was among the winners at the first Golden League meeting in Oslo.
Yelena Isinbayeva, the world pole vault record-holder, and former double Olympic sprint champion Marion Jones are just two of the other big names topping the bill in Paris.
Natasha Danvers-Smith, the Commonwealth Games 400m hurdles silver medallist and winner of the Spar European Cup final race, is the only Briton scheduled to compete.