Chamique Holdsclaw 911 -- She's 'Mentally Unstable' And Tried to Blow Up Car

WNBA superstar Chamique Holdsclaw threw a brick through the window of her ex-GF's Range Rover .... then poured gas all over her car -- presumably to set it on fire -- this according to the 911 call placed moments after the alleged attack.

The call was placed by the friend of then ex in question -- another WNBA player named Jennifer Lacy. The caller describes Holdsclaw as "mentally unstable."

According to the caller -- who sounds frantic and scared on the phone -- Chamique "tried to destroy" her ex's car ... then fled the scene.