In what may go do as the fight of the year, Gilbert Melendez defeated Diego Sanchez by unanimous decision. 
At the start of the fight, Melendez missed a head kick and Sanchez was able to get the fight to the ground. He went for a rear-naked choke, but Melendez would escape and get back to his feet. With the action back on the feet, Melendez landed several body shots.
Melendez continued to control the opening round with his strikes and opened up a cut on the face of Sanchez. As the round came to a conclusion, there started to brawl with Melendez landing a right hand that dropped Sanchez for a moment.
They continued to have their striking battle in the second round with Melendez working on the left eye that Sanchez had a cut on. The referee would stop the fight for a moment for the cage side doctor to look at the cut an the doctor allowed the fight to continue. Upon the restart, Melendez continued to score with his strikes and the fight would move into the third round.
The final round would be the best for Sanchez as he would drop Melendez and looked for a finish on the ground. Instead of going for the finish with strikes, he decided to go for a submission. The attempt would be unsuccessful and Melendez was able to get to his feet. The would brawl till the end of the fight and Melendez would score a decision victory.
UFC 166 Results:
Gilbert Melendez def. Diego Sanchez via unanimous decision (29-28, 30-27, 29-28)
Gabriel Gonzaga def. Shawn Jordan via TKO (strikes) – Round 1, 1:33
John Dodson def. Darrell Montague via KO (strikes) – Round 1, 4:13
Tim Boetsch def. C.B. Dollaway via split decision (30-26, 27-29, 30-26)
Hector Lombard def. Nate Marquardt via KO (strikes) – Round 1, 1:48
Jessica Eye def. Sarah Kaufman via split decision (29-28, 28-29, 29-28)
K.J. Noons def. George Sotiropoulos via unanimous decision (29-28, 29-28, 30-27)
Adlan Amagov def. TJ Waldburger via KO (strikes) – Round 1, 3:45
Tony Ferguson def. Mike Rio via submission (d’arce choke) – Round 1, 1:52
Andre Fili def. Jeremy Larsen via TKO (strikes) – Round 2, :53
Kyoji Horiguchi def. Dustin Pague via TKO (strikes) – Round 2, 3:51