Alistair Overeem

Brock Lesnar knows when to hang it up. He announced he was quitting the whole MMA thing after suffering a lightning fast loss to Alistair Overeem last night at UFC 141. Lesnar was floored by a brutal kick to the stomach and the fight was stopped at the 2:26 mark of round one. He said after the…

MMA pain machine Alistair Overeem -- the guy who's set to fight Brock Lesnar next month -- claims he's been stabbed in the back by his management team ... and he almost paid the price in the ring. Long story short -- Overeem filed a lawsuit against his Netherlands-based management team -- claiming…