BEIJING: Eight-time world record holder Michael Phelps sets out to hang another gold medal around his neck when the heats of the 200-metres medley get under way at the Beijing Olympics on Wednesday.
The Phelps juggernaut is at full steam after world record victories in the 400m medley, 4x100 freestyle relay and the 200m freestyle, with two more finals in the 200m butterfly and men's 4x200 freestyle relay slotted in for early Wednesday.
Phelps has ruled the 200m medley since claiming compatriot Tom Dolan's world record in August 2002 and he has steadily reduced the world mark by almost five seconds.
He is the defending Olympic and world champion and on Tuesday joined Olympic icons Paavo Nurmi, Carl Lewis, Mark Spitz and Larysa Latynina as the only competitors to win nine Summer Games gold medals with the promise of more to come.
If there is to be a challenge in 200m medley it is likely to come from teammate Ryan Lochte.
Last month Lochte clocked the third-fastest time ever as Phelps lowered his own 200m medley world record at the US Olympic trials.
Phelps must swim 17 times over nine days in order to surpass the Olympic record of seven gold by American Spitz at the 1972 Munich Games.
American backstroker Aaron Peirsol and Australians Leisel Jones and Libby Trickett are aiming for double gold in Wednesday's heats of their respective events.
Peirsol is bidding to repeat his backstroke double from Athens and won the 100m back in a world record 52.54sec today.
The laid-back Californian, a three-time Olympian, is one of the most decorated swimmers with four Olympic and seven world championship gold medals.
Lochte again looms as Peirsol's biggest threat in the 200m back after upsetting Peirsol in the event at last year's world championships in Melbourne.
Jones is eyeing the breaststroke double after breaking through for her first individual Olympic gold in today's 100m final.
She has broken the 200m world record three times and is the first swimmer to win the double breaststroke gold at two consecutive world championships.
Trickett, who won the 100m butterfly on Sunday, is the world record holder in the 100m freestyle and is set for a battle royale with Europeans Britta Steffen, Marleen Veldhuis and Inge Dekker along with American Natalie Coughlin in the free.
The heats for the women's 4x200m freestyle relay also get under way on Wednesday with the United States the defending Olympic champions.
