Thanks to his victory in UFC 7, Ruas was invited to the Ultimate Ultimate event. He defeated Keith Hackney by choke with ease, but his next opponente, Oleg Taktarov, made a tougher contest. Both fighters used a passive approach to the fight, with Ruas blocking Taktarov's takedown attempts and seizing all the opportunities to strike him, actually making him bleed profusely. However, the judges gave the decision win to Taktarov, and Ruas was eliminated from the tournament. This decision was met with controversy, and Ruas and his cornermen appealed to the referee, but nothing came from it. A year later, he faced Taktarov again in Brazil, in a bout with no judges. The rematch ended in a draw, but Ruas was clearly the most dominanting fighter, and he shook hands with Oleg after the fight. He also won the World Vale Tudo Championship (WVC) Super Fight belt in the process. He returned briefly to UFC to fight former heavyweight champion Maurice Smith in UFC 21, but lost by TKO. Ruas suffered an injury in the first round and could not continue.