nicole brewer reports. ♪ the perilous fight >> reporter: it was the star spangled flub heard round theld. ♪ so proudly we watched as the twilight's last gleaming ♪ >> reporter: five time grammy award winner christina aguilera may have earned her stripes, but her star status took a hit. >> i think that she should have known it. she's a professional singer. >> how is she forgetting the lyrics to america's song? >> it's a respectful etiquette type thing. >> reporter: with so many people so quick to criticize, we wondered if they could do better. antoine hall has reason to be confident. ♪ o say can you see >> reporter: but others should have changed their tune. ♪ o say can you see by the darkness new light ♪ ♪ what so proud we hail and i don't know that sentence ♪ >> reporter: so while most we talked to couldn't sing the first verse, i'll be willing to bet that even fewer knew a second or third existed. >> i was surprised that there were four stances. >> reporter: a professor at the college of music says we should cut her some slack. >> i give anybody kudos who is willing to sing from memo