Obviously a literal, uninformed reading of this verse can be problematic. Jesus must have had a specific context in mind when he made that statement. The context comes into focus when we consider the preceding verses, where Jesus asked, "Why then did you go out? To see a prophet?" and then answered, "Yes, I tell you, and more than a prophet" (Matt. 11:9).
Clearly Jesus was proclaiming John the Baptist to be the greatest of all the prophets, indeed even something greater than a prophet, i.e. the Precursor.