'Modern Family' -- Art Imitates Life ... with Overbearing Stage Mom

Ariel Winter stared down a crazed stage mother last night ... a woman hell bent on giving her daughter a competitive edge -- but it wasn't real life, it was the storyline on "Modern Family" ... wonder where they could've found inspiration for THAT plot line???

The episode -- which was most likely written and taped months ago -- featured Julie Bowen's character confronting the judges at an academic challenge after her daughter Alex (Ariel Winter) got eliminated.

An embarrassed Alex sees the confrontation and immediately tries to stop her mom -- "You're just mad because now you can't parade me around like some show pony!"

It all seemed eerily familiar to the non-fictional mother-daughter drama that's erupted between Ariel and Chrystal Workman behind the scenes.

As we reported, Chrystal has developed a reputation as a terror on the set ... in fact, sources say producers have blocked her from various places on the set, including hair and makeup.