Duffy is the latest in the growing list of British female singers to crack the U.S. market.
The Welsh singer Duffy's "Rockferry" (A&M/Polydor) arrives today  at No. 4 on The Billboard 200, shifting 71,000 units.
She joins Amy Winehouse and Leona Lewis as the third female British newcomer since the beginning of 2007 to see their U.S. chart debut open in the top 10. Another Brit, Natasha Bedingfield, made a big splash with sophomore album "Pocketful of Sunshine" (Epic), which powered in at No. 3 in January.
Duffy's debut effort, produced by former Suede guitarist Bernard Butler, is led by the single "Mercy," a former U.K.-chart topper which lands at No. 20 on the Adult Top 40 radio chart.
"Rockferry," is two-times platinum (600,000 units) in Britain, where it opened at the top of the Official U.K. Albums Chart eight weeks ago.