<p><br /> Simon Cowell has labelled Christina Aguilera's performance at the Super Bowl as "bad".<br /> </p><p><br /> The singer fluffed her words whilst performing The Star-Spangled Banner at one of America's biggest sporting events.<br /> </p><p><br /> Cowell said: "It sounded like 100,000 people in a stadium had just sat on a cat."<br /> </p><p><br /> He went on to say: "I always say this, this is what happens when you perform in front of an audience - even someone as experienced as Christina. You can get it wrong. That was bad."<br /> </p><p><br /> Aguilera appeared on the finale of last year's X Factor. The Burlesque star performed a duet with runner-up Rebecca Ferguson.<br /> </p>
