Welsh singer Duffy seemed taken aback by the 92-degree Austin weather: “I’ve never experienced anything like this in my life!” she said onstage. But that didn’t stop her from delivering a remarkable set at the Parish Friday afternoon with her six-piece band. The very cute twenty-three-year-old has had a Number One hit in the U.K. for the past month with “Mercy,” a dance-y go-go-style track that begs the Amy Winehouse comparisons. The songs that sealed the deal at her first U.S. gig, though, were the precise but powerful ballads: her other single “Rockferry” and the affecting “Warwick Avenue” started gentle and rose to belting, breathtaking crescendos. By the time Duffy ended her six-tune set with a pounding version of “Mercy,” the industry crowd was swaying on the club floor and entirely besotted; at least one major label (Mercury Records) has a reason to be cheerful in what looks to be an otherwise very challenging 2008.