NUMBER 1:
Marco Antonio Barrera beating Salvador Sanchez in Week 3.
Sanchez went on to become the original WBC Champion and unified that with the WBA Title...
He eventually lost his title to Kid Chocolate in Week 12.
Before the loss Sanchez was ranked #1 in the Commish's rankings.
NUMBER 2:
Vincente Saldivar beating Rafael Marquez in Week 12.
Marquez had was the original IBF Champion but he dropped the title to fight Azumah Nelson.
Marquez was unbeaten until Week 12 when Saldivar became the first man to defeat him.
(Think that's everything covered)
NOTE: This question does not include fighters records or achievments...
Despite the fact Barrera has a better record and is in the top 25.