WHEN the 100 metres and 200 metres sprint finalists line up in the blocks in the London Olympics, the world is bound to see something special. The rivalry between the Jamaicans and the Americans will again come to the fore.

Defending Olympic champion Shelly Ann Fraser-Pryce will definitely start favourite in the blue riband 100 metres sprint.

With a world leading 10.70, Fraser-Pryce blew away a top class Jamaican line up to win the Jamaican Olympic trials in fine style.

Fraser-Pryce is, however, not a shoe in as she will have to again contend with the warrior queen Veronica Campbell-Brown, who will be chomping at the bit come Olympics. Also, the ever-dangerous Kerron Stewart can never be ruled out.

However Fraser-Pryce's main threat will come from the American Olympic trials winner Carmelita Jeter, whose appetite for the big races is well documented.

Jeter has been in fine form and is the reigning world champion. She won in 10.81 at the Jamaica Invitational meet in Kingston, which was the fastest time in the world this year before Fraser-Pryce's run in June.

Jeter followed up her JN run with wins in the Samsung Diamond League before taking the US title in Eugene, Oregon.

The talented Allyson Felix, having tied for third in the US trials, could also upset the apple cart. In fact Felix beat, Fraser Pryce, Campbell-Brown and Jeter to win a diamond league event in Doha, Qatar.

But the Americans and Jamaicans may not have things their own way as Trinidadian sprinter Kelly Baptiste and Ivory Coast’s Murielle Ahoure may well spring some surprises.

While Fraser-Pryce will quite likely start favourite in the 100 metres, the 200 metres will be a different kettle of fish.

The 'Pocket Rocket' as Fraser-Pryce is known, was in imperious form when she left sprint queen Veronica Campbell and veteran campaigner Sherone Simpson, gasping for breath in her wake to clock a personal record of 22.10. However she will have to come good to better US winner Felix, who posted the fastest time this year (21.69).

Campbell-Brown is the defending Olympic 200 metres champion and can never be ruled out of any race. She will definitely be gunning to successfully defend her title.

Jeter and the evergreen Sanya Richards-Ross are sure to make the women's 200 metres in London a mouth-watering affair if they all qualify from the rounds.