The Welsh singer not only received a standing ovation from the crowd, but also from music critics who were raving about her performance: "superhuman Duffy is the life and soul (This Is London) and "

Duffy's room-shaking lungs put Shirley Bassey to shame (Daily Star). Download a totally-guilt free MP3 soul-stirring performance of "Mercy" and decide for yourself.

In related Duffy new, newcomer Estelle argued that Duffy doesn't represent soul music in an interview with The Guardian. Talking about about Duffy and Adele, she says, " I'm not mad at them, but I'm wondering - how the hell is there not a single black person in the press singing soul? Adele ain't soul. She sounds like she heard some Aretha records once, and she's got a deeper voice - that don't mean she's soul. That don't mean nothing to me in the grand scheme of my life as a black person. As a songwriter, I get what they do. As a black person, I'm like: you're telling me this is my music? Fuck that!"

Right before her gig at Royal Albert Hall, Duffy responded to Estelle's attack. "If the talent and the desire is there, I don't really think it matters what colour you are," she told Newsbeat and BBC Radio One. We don't live in the 1950s any more, we're in a multicultural country. So no, I think that's pretty far from the truth, look around and I think you'll see that it [Black Soul] really does exist."

Download Duffy "Mercy" (Live at Royal Albert Hall)