At the point in the story both these characters are at, this is really a fight of a brawn, skill, and stamina and Mori should take those more often than Asta. In the case of brawn, Asta stars off with the advantage but not only does Mori have the stat amps to close that gap at the start of the fight but his Accelerated Development does allow for him to either stay in league with or push a little ahead of Asta's own stats. Then in terms of stamina, both characters are pretty even in that regard able to fight for hours and through grievous wounds, the big difference is that Mori is able to maintain his body better than Asta can through such damage with stuff like his Acupuncture which would give him the slight edge in this department.
And finally skill. Both have Analytical Prediction and have battled others with the power so they do well to cancel each other out in that regard, and any hax that Mori could employ just isn't in character for the most part while none of Asta's would work on Mori's in the first place due to his lack of magic. So if both are only able to rely on skill, Mori takes the cake completely on this front. By this point in the series, he was already announced the god of highschool and treated as one of most skilled fighters in his series, a series of which is centered around martial arts whereas Asta while noteable in his swordsmenship does not have the same quality of skilled H2H fighters that Mori possesses. He'd be completely overwhelmed on this front and because of this, the fight would ultimately end up going to Mori.
My vote is for Mori.