With the WEC eliminating his weight class, Hendricks had to find another place to fight and signed with the Ultimate Fighting Championship. In May 2009, it was announced that Hendricks would be making his UFC debut against Ultimate Fighter 7 champion Amir Sadollah at UFC 101 in Philadelphia, Pennsylvania on August 8, 2009. In the opening seconds of the first round, Hendricks blocked a high head kick from Sadollah and countered with an uppercut, knocking Sadollah to his knees. Hendricks continued to land punches until referee Dan Miragliotta pulled him off and ended the fight 29 seconds into the first round. Some people criticized Miragliotta for stopping the fight too early, as Sadollah seemed to be trying to get up, but Miragliotta defended his stoppage, saying Sadollah was "out of it" and "still looked glassy eyed and asked me what happened."