Sanchez, fighting on Gomi's home turf, got the nod by scores of 29-28, 29-28 and 28-29.
Sanchez's best round was the first, when he successfully completed both of his takedown attempts and consistently scored with his jab.
The fight changed as it went along though, as Gomi defended the takedown and found success with his striking attack, putting the usually aggressive Sanchez on the defensive for long stretches of action.
The fight was made difficult to score because there were no huge momentum swings either way. No knockdowns, no dominant positions, and no extended time on the mat.
According to stats provider FightMetric, Gomi out-landed Sanchez 81-68.
Gomi seemed angered by the decision when it was read, but moments later, he congratulated Sanchez and raised his hand in the air.
Gomi, who had been searching for a three-fight win streak, instead fell to 34-9 with 1 no contest.
Sanchez is now 24-5.