If you really want a look at how stupid Riven is in the hands of someone competent... Twitch is there for you. Boxbox is famous for his Riven, but if you watch him play, pretty much every match regardless of what happens he just maxes E first and screws around because it's "more fun". The dude got into Challenger and stayed there despite being a one-trick pony and not tryharding because Riven's the sort of champion that's either absurdly good if you can into mechanics, or the single biggest source of salt in the game if you can't.
By the by, Darius is also a good counter to Riven. Your Q is long ranged enough that they have to burn a couple abilities to close the gap (and has sustain now!), you can stop a lot of the zoning game by pulling them into your wave or under turret (E also helps break combo chains), your passive helps you trade because it's damage that won't be shielded, and your level 6 is as big a power spike as hers is while also being better at turning 2v1 fights around. You have to go hard from level 1, be even more ballsy than the Riven. If she ever tries to CS, Q and walk away. Once you hit level two, Q+E+auto and walk away or all-in if she's low enough (you should have landed at least one or two Qs before this to waste pots and get her low). Keep zoning with Q and freeze as soon as you can. Call your jungler to farm free kills because 80% of Rivens are terrible and will always shove the lane regardless of the situation.
Also, EU LCS third place deciding matches. My god. Those plays. Such EU.