Along the course of his or her competitive career, an MMA fighter is almost certain to navigate peaks and valleys--a series of highs and lows defined by tremendous victories and agonizing defeats. The top fighters enjoy those peaks far more frequently in their careers, periods when they seem almost invincible, as is the case for current UFC Light Heavyweight champion Lyoto Machida.
Many fighters will also experience lows that indicate their career is nearing the end, as appears to be the case now for the legendary Chuck Liddell. And while MMA will probably never have its own Rocky Marciano, the former boxing champion that retired undefeated, the cream of the MMA crop is expected to maintain its standard of excellence once it has been established.
However, there are those fighters that sometimes simply baffle fans with their performances; fighters we just know are way better than they often perform, and go through more letdowns--in either performance, result, or often both--than we know they should.
The following is a list of MMA fighters that often fail to live up to their billing. Some surprise us with wins, but most have shocked us with losses or subpar performances that we know are beneath them.