[2007] This really convinced me! Utada is THE best!

[Dustie]

Utada was really worn off during that performance. I think it was the last one of her tour, when they recorded it. She appeared on some Tetris DS event in-between and she could barely speak. Ayu barely ever has such problems (until now, that she's partly lost her hearing).

I think Utada barely ever had any vocal training, just went on by herself, which is why she wore her throat off during the tour. Ayu could barely sing when she met Matsuura and she's been recieving professional vocal training since then. She's been doing regular TV lives for years, which advanced her vocal skills. Utada barely appears on such lives and only had two live tours in her whole career. Her voice doesn't get the exercise Ayu's voice's been getting over the years.

I think Utada has less technical background in vocals than Ayu. Utada is sorta a natural, where Ayu was simply tought how to sing.