If sasuke fought Minato, Sasuke would have to use Susanoo to go on the offensive to avoid being tagged, if he gets tagged with the ftg seal, Minato can end the fight whenever he chooses, remember in the movie Minato had a Shuriken shadow clone jutsu where he threw one Shuriken and it turned to countless more.
If he did this with his special ftg kunai, he could attack from too many directions, Sasuke took out 100 guys without killing them, but Minato killed entire platoons in the blink of an eye, without using hardly any chakra. In the war I believe it was stated Tsuchikage stated his ppl were to flee on sight. Tsuchikage's village is considered one of the strongest in terms of Military strength but they were ordered to flee one man on sight.
What more needs to be said?