Considering the many missteps both Casey Abrams and Haley Reinhart have taken throughout the season (see: Casey’s off-putting “Smells Like Teen Spirit” and Haley’s wobbly “Blue”), it was quite a delight to see the contestants duet to the jazzy “Moanin’ ” during last night’s results show. Look at them! Both were in tune! Passionate! Fun! The performance demonstrated just how much stress factors into the competition: solo, Casey and Haley have the tendency to veer off-key, wander aimlessly on stage, and far too often rely on old tricks (which, for both, incidentally, is the angry growl). Together, during a no-consequences-attached performance, they knew exactly what to deliver: A well-plotted performance that truly showcased their smooth vocals and spoke to their undeniable, ahem, chemistry. (And, considering the song title, the angry growls actually made sense.) So, I ask you, PopWatchers: Was “Moanin’ ” the best performance of the season? (I’ll put it in second place in my book, below Casey’s undeniably gorgeous “Georgia On My Mind.”) Dare I say “Moanin’ ” even topped Idol’s previous best duet of all time, Adam Lambert and Allison Iraheta’s “Slow Ride”? (Ducks and covers.) Watch both performances after the jump and let me know what you think.