What would you do if a very close friend corrects you when you call him a best friend?

This came up after his B-day party. All I did was state that it was great to meet my best friend's friends. The next day he sent me this text out of the blue correcting me and telling me he has no best friends and that he has only good friends. This came as a shock since we share and talk about very personal issues and he have been hanging out on a nightly basis for over 4 years. Is this so called best friend as I claimed he was not a friend at all?