riven vs yasuo

usually

Everyone loses when either champ is involved.

Nobody likes the majority of their mains. :/

Riven's kit is much more straight forward, requiring less need to mechanically outplay your enemy. She also has stronger defense built into her kit.

Their playstyles are also slightly different. They can both start with a very engage-harass-disengage until they can all-in and kill their opponent, but when Riven gets a bit of sustain, her harass phase gets smaller, until it disappears completely. This actually counters Yasuo pretty harshly.

riven wins of course. nothing yasuo has stops rivens attacks

Whomever gets more ganks

Yasuo wins once he has PD if he hasn't fed too hard by then. He's also stronger lvls 1 and 2 and can leverage that advantage into an easy lane if done properly. But if Riven ever gets ahead, there's 0 coming back for Yasuo.

It's fairly skill dependent. Both have tools that would win it for them, but the players have to use them correctly. Ex, Yasuo can kite Riven with E and poke her with Q while she trys to gap close, but Riven can instakill a low Yasuo with R slash, but Yasuo can W it and walk away. There's a lot of X factors for high skill cap champions. Late game, full build, 1v1, same skill level, Yasuo has more tools to beat Riven, primarily negating Wind Slash.