Number 10 does'nt replace number 1 if they meet and number 10 wins. Rememberwhen Vernon Forrest beating Shane Mosley, Mosley was considered number 1 at the time, guess what Forrest was never regarded as even being close to the top spot. I clearly remember Larry Merchant telling him because you beat tiger Woods doesnt mean you're Tiger woods. So to answer your question if they meet tomorrow and Hatton wins Hatton wont be number 1, although floyd will also not be number 1 anymore.