Matt Riddle is one of a very small number of fighters to have entered the UFC in the modern era with zero professional fights under his belt. He actually had begun teaching himself Brazilian Jiu-jitsu using UFC legend B.J. Penn's book Mixed Martial Arts: The Book of Knowledge, while working as a roofer to make ends meet. Things changed very quickly for Riddle after he tried out for The Ultimate Fighter reality show. He made the cut, and was paired up with Dan Simmler, a student of former UFC welterweight champion Matt Sera, for his fight to make it onto the show. Riddle knocked him out in the second round, breaking his jaw in two places. The finish was called the biggest knockout in Ultimate Fighter history by UFC President Dana White, and the knockout of the century by Quinton "Rampage" Jackson, one of the coaches on the show that season. Rampage would go on to choose Riddle second during the fighter draft on the show. While Riddle didn't win the show, he did earn a UFC contract out of the appearance. He also wound up in a feud with Dante Rivera, a fellow fighter on the show. Rivera was quoted as saying he would retire if Riddle beat him. In the first UFC fight for both fighters, the two would be paired up. Riddle beat Rivera by decision, and Rivera was released from his UFC contract. He did not, however, retire.