I had a situation where an employee and myself evaluated each other.  I remained professional and neutral or positive.  She, on the other hand, was quite negative.  I have suffered because of this.  I have tried several times to bad mouth her but just can’t bring myself to do so.  It is a difficult situation.
Did you give just your professional opinion about this coworker?  Did you keep the personal opinions out?  That is the best way to do it.