Mario Williams' baby mama is going to bat for the ex-NFL star ... she says she wants his charges dropped -- this despite him allegedly breaking into her home and wildly yelling at her last month.
Mario -- the former No. 1 overall pick in the 2006 NFL Draft -- was arrested back on Aug. 20 after cops say he made a copy of a garage door remote and illegally entered his baby mama Torie Porter's Texas home.
TMZ Sports obtained video of the standoff that happened when Porter confronted the 6-foot-7, 290-pound former pass rusher at her garage door ... and it's intense.
Williams accuses her of using their child's iPad to gain access to the contents of his iCloud ... and she fires back by constantly saying, "How did you get in here?"