Tina Fey and Amy Poehler -- Because Y'See ... Bill Cosby Jokes Kill at Golden Globe Awards

Tina Fey and Amy Poehler did what they said they would do ... take shots at Bill Cosby during their opening monologue at the Golden Globe Awards -- and they went in HARD!

Tina and Amy turned their opening into a full roast of Cosby's rape allegations -- each doing impressions of the Cos talking about slipping pills to unsuspecting women.

Perhaps surprisingly, the Hollywood crowd ate it up. There were a few shocked faces, but only a few.

Of course, Cosby has never been convicted and vehemently denies the allegations ... so we're guessing he wasn't laughing.