World record holder Asafa Powell can even the score when he lines up against Olympic champion Justin Gatlin in the 100 metres at the London Grand Prix on Friday.
Gatlin was given the verdict over Powell in their only other meeting this year in Eugene, Oregon although both were timed at a wind assisted 9.84 seconds.
"That wasn't really a race for me," the 22-year-old Powell told reporters on Tuesday. "I was only 95 percent fit and I didn't run to my full potential."
The Jamaican ran a world record 9.77 10 days later in Athens's Olympic stadium, the scene of Gatlin's surprise triumph last year.
The pair is due to meet in Rome earlier this month but Powell withdrew with a groin injury. Gatlin won the race in 9.96 seconds.
"Yesterday I trained and felt very good. It felt like the old Asafa Powell," he said.
Talking about his main rival for the 100 title at next month's world championships in Helsinki, Gatlin said: "The best acknowledge each other I think, and right now we see each other as the best out there.
"I feel confident when I race against him. I feel confident when I race against other people. I just know that I need my A game because I know spectators are watching, critics are watching, especially when we go head-to-head," the 23-year-old American added. World champion Kim Collins and former world and Olympic champion Maurice Greene are also in the field. Home hopes rest on Olympic 100 metres relay gold medallist Jason Gardener.
Women's pole vault world record holder Yelena Isinbayeva of Russia has said she will attempt to break the five metres barrier if conditions are right on Friday.
The 23-year-old Olympic champion has already set two world bests this month, sailing over 4.95 metres in Madrid last Saturday to beat her previous record of 4.93 set on July 5.
AMERICAN SWEEP
The two fastest 400
Wariner, 21, saw off his training partner Williamson to win the U.S. championship in 44.20, the fastest time this year.
An American sweep is likely with world silver medallist Tyree Washington, who won the Rome Golden League, and Andrew Rock, third in the U.S championships, also running.
Ethiopia's world 10,000 and 5,000 metres record holder Kenenisa Bekele competes over the shorter distance at Crystal Palace.
He came close to breaking the 5,000 metres world mark at the Paris Golden League meeting earlier this month when he ran the fourth fastest time ever of 12 minutes 40.18 seconds.
A long unbeaten run must come to an end when the top two in last year's Olympic final, Veronica Campbell and Allyson Felix, face each other over 200 metres.
Campbell has not lost since March 2000 while Felix is unbeaten since finishing second in Athens to the Jamaican.
U.S. champion Sanya Richards, who pulled off a surprise win over Olympic gold medallist and 2004 Golden League jackpot winner Tonique Williams-Darling in the Lausanne Super Grand Prix, tops the bill in the 400 metres where she faces world champion Ana Guevara.
Britain's Olympic 1,500 and 800 metres champion Kelly Holmes will make her final appearance at Crystal Palace in the 1,000.
The 35-year-old, who has been struggling with an Achilles problem this season, may continue running until March's Commonwealth Games in Melbourne but will retire after that.
