After the battle the Union made a pursuit with a small force under Sherman. At Fallen Timbers Forrest led an impromptu charge against this small force with roughly 400 cavalrymen. Forrest cut right through the Union lines in the charge. This small event caused Sherman to halt the pursuit and return to his camps. The Union made no other pursuit. Forrest was clearly outnumbered but he made his charge hoping to stop the Union, just like he did. The Fallen Timbers site had a lot of felled trees which would hinder movement and this seemed like the place to halt the Union.
Forrest could have tried some other way to halt the Union. In retrospect we can see that Sherman probably would have stopped at his first resistance. There are any number of ways Forrest could have halted Sherman. A few cannon may have been enough to convince Sherman to halt the pursuit. The way Forrest ended the pursuit was dramatic but it could have ended much less dramatically.
Its a significant action but one that is not critical because the Confederate rear guard would have done something to halt this small pursuit. Forrest just ended the pursuit in dramatic fashion.