The director of Batman v Superman: Dawn of Justice, Zack Snyder, has explained why Batman has an advantage over Superman.
Technically speaking, Batman should lose against Superman under most circumstances. This is obviously because Batman is not a super-powered alien. However, Snyder explains there is an advantage Batman has over the Kryptonian.
During an interview with Total Film magazine (via ComicBook.com) Snyder says “the advantage that Batman has is the goodness of Superman“. He went on to say that Batman can exploit Superman and he likes to play dirty too.
This is a sign that Kryptonite comes into play at some point in the fight. Not to mention Batman in Dawn of Justice has a lot of anger towards Superman in the movie. Superman on the other hand wants to clear his name and be a good guy after making such a big mess in Metropolis in Man of Steel.
Snyder’s comments may also indicate Superman might be holding back his full power against Batman. Superman does not want to kill Batman so he might be only using some of his strength during the fight. Batman on the other hand can do whatever he wants and can use full power.
It will be interesting to see if a winner is actually crowned in Batman v Superman: Dawn of Justice. However, the fight could end without a winner if another character comes in and breaks them apart…