Next week at World Series of Fighting 8, Derrick Mehmen looks for his fifth straight win. Watch him notch win No. 4 in spectacular fashion. This past September at WSOF, Mehmen fought fellow heavyweight Rolles Gracie and earned Knockout of the Year consideration for his highlight-reel stoppage. Check out the full video above. And catch Mehmen (16-5) in action against Scott Barrett (14-3) on Jan