Raphael vs KillerCroc
a sewer brawl! both so happen to cross paths along the sewer ways and it gets violent. Raphael has his basic sais.
round 1 - they fight.
round 2 - both are lost to rage.
http://en.wikipedia.org/wiki/Raphael_%28TMNT%29
http://en.wikipedia.org/wiki/Killer_Croc
Honestly im unsure if it gives anyone an advantage if its a sewer in NY or Gotham so lets just say its one unknown to both but one they had time to adapt to so its even grounds on that.