In this video, we see an incredibly BRUTAL knockout when a boxer fights a combat sambo practitioner in a mixed rules type bout.
To tell them apart, the boxer is the one in the boxing style boots while the sambo guy is the guy with the one white shin pad on.
Now, boxing can be a great style for self-defense and boxing techniques are definitely a part of MMA but boxing alone is simply not enough to compete in an MMA type bout, especially against a grappler.
Combat Sambo, on the other hand, is much closer to modern MMA with practitioners being trained in both grappling and striking, including all facets of striking (e.g. kicks).
Fedor Emelianenko, arguably the greatest heavyweight in MMA history, comes from a combat sambo background and even continued to compete in sambo during his MMA career.
In this video, though, we see the boxer looking pretty good early on, showing some good footwork and jabbing ability, but the combat sambo dude has something up his sleeve.
You see, pure boxers, if that is what this guy is, aren't going to be used to kicks coming at them and aren't going to know how to defend against them or when they are even in danger of being kicked.
The kicks, particularly the head kick, is ultimately what ends this fight in EXTREMELY brutal fashion. Just watch the video below and see for yourself.
ABOUT COMBAT SAMBO:
Utilized and developed for the military, combat sambo resembles modern mixed martial arts, including extensive forms of striking and grappling. Combat Sambo allows punches, kicks, elbows, knees, headbutts and groin strikes. Competitors wear jackets as in sports sambo, but also hand protection and sometimes shin and head protection. The first FIAS World Combat Sambo Championships were held in 2001. The World Combat Sambo Federation, based in Russia, also sanctions international combat sambo events.[Source: Wiki]