I've just finished my fourth year (out of 5) of biology studies in one of European universities. I have some experience in research and my grades are quite ok (in US scale it would be 3.75, which means I'm in 5% of the best students in my university). This year I'm starting my master thesis and I expect it to be rather successful - I have interesting topic and good supervisor, with whom I have good contact. This year I'm also starting new studies in electrical engineering and I would love to work in biomedical engineering.
There are several PhD programmes I would like to join abroad (mainly US, UK and Germany). However, I have just got my grade for a research project from spring semester, which is really bad (C+). It is my only grade lower than B, but since it's in research (actually, it's my only grade in research), I'm afraid that it might be a big obstacle in admission process. I'm not a kind of person who blames everyone for my failures, but this time I cannot explain it in any other way than bad supervisor who didn't like me. I've learnt many methods during this project and I've done the worst job for the research group. I've also learn a lot about research in general by seeing my supervisor's mistakes. That is why I'm really happy about this experience, but it doesn't change my grade.
My question is: is there anything I can do to make this grade seem less important or to explain it to admission committee? I'm pretty sure that "Supervisor didn't like me" is not what they want to hear.