Michael Phelps will end his comeback meet with a 100 metres freestyle showdown against Frenchman Fred Bousquet after winning his preliminary heat at the Charlotte UltraSwim Grand Prix.
Returning to competition for the first time since his record eight gold medal haul at the Beijing Olympics, Phelps's final event at the four-day meet should provide him with a good fitness gauge following the longest layoff of his career.
The 23-year-old American will be joined in the final by Bousquet, the 50 freestyle world record holder and Ricky Berens and Cullen Jones who both won relay gold medals in Beijing.
While Phelps has not revealed his programme for the 2012 London Olympics, the 100 freestyle is expected to figure prominently in his plans.
Although he rarely competes in it, Phelps has the world's ninth best time in the event with only three men, Frenchmen Alain Bernard and Bousquet and Australian Eamon Sullivan having swum faster.