Yes, Jon Jones has an official loss on his professional mixed martial arts record, though it came under unique circumstances.
Details of the Lone Defeat
Jon Jones' only professional mixed martial arts defeat occurred against Matt Hamill at The Ultimate Fighter 10 Finale in 2009. This was only Jones' third appearance in the Octagon. During the fight, Jones was largely dominating Hamill, even causing a shoulder dislocation through a takedown. However, Jones was subsequently disqualified for utilizing illegal downward elbows while on the ground.
Despite controlling the fight, the illegal strikes led to the stoppage, resulting in an official disqualification (DQ) loss on his record.
Here's a summary of the fight details:
| Opponent | Event | Year | Outcome | Method |
|---|---|---|---|---|
| Matt Hamill | The Ultimate Fighter 10 Finale | 2009 | Loss | Disqualification (Illegal Elbows) |
The Nature of the Loss and Perception
Due to the nature of the loss—a disqualification rather than a defeat by knockout, submission, or judges' decision where he was outfought—many fans, analysts, and even the UFC itself often regard Jon Jones as effectively undefeated in terms of competitive performance. The loss was a consequence of a rule infraction rather than being bested by his opponent.
