One of the great things about this sport called MMA is that anything can truly happen. While a favourite of a fight ends up winning a lot of the time, there are often times when the underdog ends up with the W next to their names.

We at Fight of the Night have put together what we believe are the biggest upsets in MMA (well some of them anyway).

Marco Ruas loses to Alexander Otsuka : Pride 4 : Mixed Martial ...

Marco Ruas vs Alexander Otsuka – Pride 2

For some reason, this fight often has often been overlooked on other ‘Biggest MMA upsets’ lists that are seen around the internet. However, this fight deserves to be noted as one of the most surprising upsets the sport has seen to date.

Ruas was viewed as one of the most feared and solid fighters in MMA at the time, and one of the first prominent Brazilian fighters with an elite striking game. Otsuka, on the other hand, was a highly durable pro-wrestler with basic striking and grappling skills.

Otsuka took the fight to Ruas for two rounds before the fight was stopped before the third round got underway. While the early Pride events were known for having worked fights, this fight was not of them. Word was that Ruas was extremely sicks prior to the bout which may have hindered his performance.