By Greg Stutchbury
SHANGHAI (Reuters) - Michael Phelps should have a clearer picture of what he needs to do to ensure he is still a dominant force in the pool at the London Olympics with the final of the men's 200 meters butterfly at the world swimming championships on Wednesday.
With day four of the pool competition also marking the one-year countdown to London 2012, the 26-year-old American will be looking to atone for a series of recent losses in what has been his signature event for the best part of a decade.
So dominant was the world and Olympic champion, he had not been beaten in a 200 butterfly race for nine years until he lost to China's Wu Peng twice and Australia's Nick D'Arcy earlier this year.
D'Arcy did not make the Australian team after being ill at the time of the national championships and selection trials in March, but Wu will be beside Phelps in lane two on Wednesday.
Phelps conserved his energy during the heats on Tuesday and qualified for the semi-finals in 11th, before he qualified for the final in the third fastest time, about 90 minutes after he had been pipped by Ryan Lochte in the 200 freestyle final.
"The reason why I haven't swum as fast as a couple of years ago is all my fault," Phelps said of his recent struggles. "I know that if I train as much as I was supposed to at a consistent level, I can swim as I wanted.
"Now I feel like I'm coming back to my old self."
"I think I can win if I swim like I did in Rome 2009," she confidently said after her semi-final.
China, already riding a crest of a wave after two gold medals in the pool, will be hoping to add a third with the gangly Sun Yang the fastest qualifier for the men's 800 freestyle final.
Norway's Alexander Dale Oen will be attempting to add another medal to the 100 breaststroke gold he won on Monday in the final of the 50 breaststroke.
(additional reporting by Soo Ai Peng)
(Editing by Dave Thompson)