How do you play against riven's counter's?

I have a huge problem with basically all of her counterpicks, anything that counter's her, i just can't deal with at all. I usually end up feeding pantheon as an example when i play her.

From what i understand, she has a hard time outside of mid game so how do i survive a game versus a champion that counter's me when i'm playing riven? What do i do? I don't know, i honestly don't.

Edit: The obvious answer is "Play safe" but while i can do that, what do i do after that, what do i do during mid game as an underfed riven who can't do much.

PS: Jayce's knockback tilts the crap out of me.