Board Thread:Supergirl discussions/@comment-1998684-20170328130718/@comment-27700324-20170403182343

MektonZ wrote: Daxamites are weaker than Kryptonians in the show.

Different versions of the characters, but If you want to see a fight between both, you can check this issue:

Supergirl and the Legion of Super-Heroes 25

A "Supergirl" and Mon-EL also fought in this issue, but that Supergirl was not even Kryptonian.

Maybe they fought in some Pre-Crisis issue, but neither comes to mind. Only time that Supergirl "fought" Mon-El in Pre-Crisis is when Supergirl was brainwashed into seducing Mon-El into a cave filled with lead lining. It was the very early Legion comics.