Complex sentence: Known as "Macho", Miguel began his professional career in 2003, and lost both fights in which he stepped up in competition, to Raúl Márquez and Luis Ramon Campas in 2006.
Split into simpler sentences: Known as "Macho", Miguel began his professional career in 2003. When he he stepped up in competition, he lost both fights: to Raúl Márquez and to Luis Ramon Campas in 2006.