Top five means nothing without streams. Natalie La Rose was top 5 with Around The World but her lack of streams gave her a top 20 peak on the Official Chart
Sax won't under perform, it's being used on like 6 commercials, I literally can't stop hearing it on TV.
Plus with all the X-Factor plugs and the future X-Factor performance, I see it being a huge hit.
The iTunes preview is really nice too. Simon's put a lot of backing behind this song, he's not going to let it flop.