Career
He also fought at the 2008 Olympics. In Cartagena at the Caribbean Games 2006 the 212 lbs Rivas lost in the first round to Cuban Olympic Bronze medalist Michel López Núñez 4:6
In the Pan American main event in Rio he beat Gerardo Bisbal 22:8, Didier Bence by walkover (injured) and reached the final but lost to Alfonso once again, this time 4:8. In Chicago at the 2007 AIBA World Boxing Championships he stopped Dominican Lequan Carlisle but lost to eventual silver medalist Vyacheslav Glazkov 7:23.
At the first Olympic qualifier in March 2008 he lost to American Michael Hunter junior
However, in April 2008 he qualified for the 2008 Olympics through the second American qualifier with a 16:4 over Mexican Andy Ruiz and a 6:5 victory over Brazilian Gleison Abreu.