I am not sure that it is possible to understand this sentence correctly out of context. When I read your translation, I thought that Confucius was just being modest. But after reading JoanTaber's link, I realised that he meant something like "at least one of the other two can teach me something". You see, we are accustomed to think of the pupil-teacher relationships in Asian countries (and especially in the past) as comprehensive and covering all areas of the pupil's education and life. It may be a stereotype, but it is a stereotype that is shared by many, many people. So when I read that one ancient Chinese person says about another person that the latter is good enough to be his teacher, it makes me think that the first person thinks of the other one as his better in all respects.Confucius, a famous Chinese educationalist, said "If three of us are walking together, at least one of the other two is good enough to be my teacher."
I wonder if you can understand this translation completely.