Last night Gwen Stefani performed at Manhattan's Hammerstein Ballroom for a room full of MasterCard customers as part of the credit card company's Priceless Surprises series. If YouTube's to be trusted, the setlist mined her formidable pair of solo pop ventures Love. Angel. Music. Baby. and The Sweet Escape rather than the No Doubt material (despite the gig's proximity to the recent 20th anniversary of Tragic Kingdom). Things got personal in the encore as Gwen dug out a new song called "Used to Love You." The cut Gwen advertised on Twitter as her next single finds the singer, who late this summer filed for divorce from Bush singer Gavin Rossdale, her husband of nearly 13 years, refusing to mince any words: "You thought there were no boundaries, but you just pushed me too far / I guess nobody taught you, nobody taught you how to love," Stefani snipes in the song's pithy second verse. 20 years ago Gwen was breaking up with a different boy in a different band (that time her own) and ended up writing "Don't Speak," one of the biggest songs of the decade. It's too early to pin anything on "Used to Love You," but it's unforced and genuine in a way Gwen's last few comeback singles haven't been. Stream "Used to Love You" below.