Preliminary reports predict that American Idol runner-up Clay Aiken will upstage winner Ruben Studdard in the charts.
The two individuals have released their singles on the same day: Aiken's version of Simon and Garfunkel's 'Bridge Over Troubled Water' is outselling Studdard's cover of 'Flying Without Wings' by Westlife.
Online retailer Amazon's sales chart puts Aiken at the number one spot, and Studdard at number nine.
Out of 24m votes cast – Studdard beat Aiken by a marginal 130,000 votes in the American Idol 2 final on US television in May. Studdard and Aiken have albums due for September to release their first albums.
38m people watched the final.
A third series of American Idol is being planned for nest year.