Playing Against Bruiser As Assasins

Recently, I could not win games as an assassin because of fed top bruisers. I know that the adc is key to countering juggernauts or top bruisers in general. But, I have had games where the adc was "bad" or like "did not know how to adc." I mean yes, i do help out bot by roaming, but as mentioned before, the adc does not know how to play his role, being "useless" in team fights. So, in general, if your team's adc is bad, and the enemy top bruiser is fed, then would you "lose" the game because there's only so much you can do as an assassin? Or do you know a way to somewhat win the game? I heard in Bronze and Silver, there are many adcs who do not know how to play their role, so I would like to know such ways to win. Thanks!