Sheeran. Though this performances was at a concert in Dallas, in a smart promotional move, the performance was broadcast for Macy's 4th of July parade. Swift has an incredible track record of losing the key through a performance, she stayed comfortably in tune, and kept the sassy body movements to a minimum.
The moderato duet, which is strangely the 4th Mainstream radio single from Red (while the electronic hook laced title track is sent to Country, as if that will help her Country image), came off as nothing short of charming. Swift's voice was thicker than usual (especially in the lower register), and were (dare I say) rather impressive. Is any singer shaking in their boots after this? Hardly. But I think this might have made Selena Gomez emotionally unstable.
Overall: B-