IIWAB did as did SL. Beautiful Liar: 'It is one of the few singles to debut at number one on both the US Hot Digital Tracks chart and US Hot Digital Songs chart.'
No, We Belong Together peaked at #2 in June 2005. It was held off by Hollaback Girl.
Here's its Digital Songs chart run:
27-17-12-11-9-2-3-4-3-2-3-3-7-8-11-13-15-18-19-20
But Don't Forget About Us and All I Want for Christmas is you both reached #1 on iTunes in December 2005.