When it comes to showdowns, athletics has seen nothing like it since days of Ben Johnson v Carl Lewis more than 20 years ago.
Usain Bolt, the triple Olympic champion, against Tyson Gay, the triple world champion. The fastest man ever over 100 and 200 metres against the fastest man of 2009 over both distances. The extravagant crowd-pleaser against the "boring" one.
However, Sunday's 100 metres final (0:05 IST, Aug 17) and the 200 on Thursday represent only a flashing 30 seconds of what should be an entertaining nine days.
It all takes place on the iconic blue track of Berlin's Olympic Stadium and officials have not been afraid to ride the exploits of Jesse Owens there at the 1936 Olympics.
The United States team will wear kit with the initials JO stitched in while the descendents of Owens and German long jumper Luz Long will present the medals for the men's long jump.
In the 1936 Games, Luz famously gave Owens advice on his run-up after the American had fouled his first two jumps. He made his third safely and went on to win the event, along with three golds on the track.
Luz took silver and the two men walked from the stadium, arm-in-arm and became lifelong friends despite the political pressures within Germany at the time.
The relationship between Bolt and Gay is unlikely to be so enduring. Though there is none of the bristling animosity that marked the Lewis-Johnson rivalry, today's best sprinters rarely get beyond a "hi, how's it going?" when they pass.
'EXCITING INDIVIDUAL'
"Usain Bolt is a very exciting individual. He's fun and he has a lot of personality and is exciting. And he backs it up," Gay said this week. "I'm probably what you call boring."
Times of 9.77 for the 100 metres and 19.58 over 200 would not generally be called boring. If Gay's persistent groin problem holds out and he gets good starts the American has the chance of unsettling Bolt in what, with Asafa Powell also hoping to have a say, could be two of the sport's all-time great races.
The women's sprints look more open, particularly the 100 where seven competitors have broken 11 seconds this season.
Olympic silver medallist Kerron Stewart is the form runner and her 10.75 in Rome was the fastest for nine years.
Compatriots Shelly-Ann Fraser, the Olympic champion, and Veronica Campbell-Brown, the world champion, will also be in the mix while the American challenge is spearheaded by Carmelita Jeter, seemingly peaking at the age of 29.
Campbell-Brown could have a stronger chance in the 200 metres, where she is the Olympic champion, but the favourite to make it three world titles in a row is American Allyson Felix.
As with Bolt and Gay, American 400 metres rivals Jeremy Wariner and LaShawn Merritt have avoided each other all season but they know each other well enough.
Merritt finally stepped out of the shadows to beat Wariner in the Olympics last year and is confident he can prevent his compatriot completing a hat-trick of world titles.
Yelena Isinbayeva is also seeking a third successive world gold in the pole vault and, until a month ago, looked an unbackable favourite.
An early exit at last month's London Grand Prix showed she is human but, with Olympic silver medallist Jennifer Stuczynski pulling out this week with an Achilles injury, even a below-par Isinbayeva looks good enough to win.
Kenenisa Bekele already has three world golds to his name over 10,000 metres and is seeking to match compatriot Haile Gebrselassie by making it four in a row.
The world record holder's chances were boosted Friday by the injury-withdrawal of compatriot Sileshi Sihine, the man who habitually follows him over the line at major championships.
Sihine's wife Tirunesh Dibaba has also pulled out of her defence of the 10,000 metres but could still run over 5,000.
