UFC on FOX Results: Unfortunate Ending to Mackens Semerzier vs. Robbie Peralta

Big John McCarthy is one of the best referees in mixed martial arts, but even the best can't see everything all the time.

The preliminary bouts for the UFC's debut event on FOX this evening are currently airing online and featherweight-fight Mackens Semerzier vs. Robbie Peralta has just come to an unfortunate end.

Early in the third round, Semerzier and Peralta were exchanging on the feet when they inadvertently collided heads.

Semerzier was badly rocked by the collision and fell to the ground.

Headbutts are illegal under the unified rules of MMA and, as such, the fight should have been temporarily halted as soon as the accidental headbutt occurred.

However, referee John McCarthy was not in a position to see the headbutt occur and the fight continued.

Semerzier did his best to comeback after the unintentional illegal blow, but Peralta swarmed on him and prevented Semerzier from recovering.

Peralta landed several unanswered shots on the ground and McCarthy stopped the fight.

It's always unfortunate to see a fight end like that, but it's not the first time we've something like that in MMA, and it won't be the last.

In the past, we have seen fights with controversial endings overturned because of appeals to the athletic commission, so there is a chance that this bout will eventually be ruled a no-contest.

Until then, the fight will appear as a TKO victory for Peralta.

Be sure to stay tuned to Bleacher Report for all things UFC on FOX. B/R is your home for complete coverage of the November 12 fight card, from pre-fight predictions, to in-fight coverage, results and post-fight analysis, which you can find out at our event hub page.

Andrew Barr is a Featured Columnist for BleacherReport.com. For updates on what's happening in the world of MMA, follow him on Twitter http://twitter.com/#!/AndrewBarr8.