When Marco Antonio Barrera steps back into the ring against the slippery Paulie Ayala he won?t just be gazing across the ring at a very serious challenger, he?ll be looking inward, perhaps wondering how he fell from the elite of boxing so quickly and so dramatically. Barrera?s dismantling at the hands of Manny Pacquiao in 2003 was so complete and so violently overwhelming that many were calling for his retirement.