Usage when considering only two things
In many languages, including English, traditional grammar requires the
comparative form to be used when exactly two things are being considered, even in constructions where the
superlative would be used when considering a larger number. For instance, "May the better man win" would be considered correct if there are only two individuals competing. However, this rule is not always observed in informal usage; the form "May the best man win" will often be used in that situation, as it would if there were three or more competitors involved.
https://en.wikipedia.org/wiki/Comparison_(grammar)