The fight began and the fighters came out and circled. Arona landed a leg kick and then another early. Jackson landed a body shot and Arona backpedaled. Arona delivered a leg kick. Arona landed another leg kick. They clinched and Arona delivered a knee before going into standing guard. Jackson carried Arona over to the corner of the ring and laid him down into a laid-down guard. The referee stood the fight up and again restarted the ground position in the center of the ring. Arona tried to go for an armbar but Jackson stood up and delivered kicks from the standing position. The referee stood the fight up. Arona pushed forward, delivering a body shot and then a body kick to the liver. Arona went down to the ground purposefully but stood when Jackson didn't go for it. Jackson landed a hard shot. Arona went for the takedown, pulling Jackson down into his closed guard. Arona looked for an armbar on Jackson's right arm, but Jackson wasn't having any of that. Jackson landed shots from the top. Arona tried for a triangle and Jackson tried to stand but took some upkicks and some strikes from the bottom and he got cut above his right eye, bleeding badly. Jackson looked hurt and he struggled to survive and laid on top. Arona tried for a kimura and then again. The referee asked if Jackson gave up and Jackson had a look on his face that clearly showed that he was still in the fight. He broke free. Jackson landed a strike from the bottom on Arona's nose. Arona was looking for a guillotine and then a triangle right after, delivering strikes from the bottom at the same time. Jackson grabbed Arona up while he was in the triangle and slammed him hard, punching him twice after he landed. Rampage Jackson knocked out Ricardo Arona and earned his title shot against Wanderlei Silva.
Some think that when Rampage slammed Arona down, Arona's head may have bounced off the mat into Rampage and they had an unfortunate headbutt, which is what KO'd Arona, not the slam itself. This means the fight should be ruled a NC. Rampage also had two cuts on his forehead after the slam that look to be inflicted by Arona's jaw/teeth maybe.