Former UFC champion Demetrious Johnson agrees that Jon Jones has lost one fight in his career.
"He lost to Matt Hamill. Yes, he bloody lost. He broke the rules. A defeat is a defeat. Whether you win by a second or five miles, a win is a win. He has 28 wins and one loss, he lost to Matt Hamill on December 5, 2009 by disqualification. Banned elbow strikes. That's still a defeat. His record stands at 28-1-1. Has Jon Jones ever been defeated early or anything like that? No, that hasn't happened. But he was disqualified, which resulted in a defeat, so he did lose."
