Who counters Riven best?

I've been seeing her nearly every match and it's making me sick to my stomach. Top lane almost always loses to her and if not, she roams and gets her kills elsewhere and always manages to get fed and just dominate. I tend to play support, so I'll ward around the lane to keep her from ganking, but teammates at my elo tend to respond like a sack of potatoes and stay pushed even when they know she's coming. I decided I was going to swap to top lane and wanted to know who counters her best? I've never had to deal with such an annoyance since Xin Zhao.