What's worked for me in the past is be calm, approach the person, ask if they have a few minutes to talk in private, and ask "I've been sensing you are unhappy with my work performance.  If so, how can I improve?  Do you have any suggestions?  I'd like to resolve this so we can have a better working relationship."  If you feel comfortable with this, then go for it.  I have found when I am direct in a non-confrontational manner, I get better results.  Good luck!