Caitlin Clark and a courtside fan got into such a bizarre tiff on Wednesday night ... security guards actually had to get involved in an apparent effort to cool things off.
The curious scene all unfolded in the first quarter of the Indiana Fever's playoff matchup with the Connecticut Sun ... following a foul call on the floor.
After appearing to exchange words with a man in the second row, Clark got the attention of the refs -- and pointed at the guy.