How to counter Yasuo
Let us take a look on how to beat Yasuo. We will look at champions who are strong against Yasuo and who are weak against Yasuo. Use win rate, gold difference and creep score difference at minute 10 to find the best 
Mid champion who counters Yasuo. You can already win in champion select with the right counters for Yasuo. If you want to know how to counter Yasuo then you need to take into account the best picks vs Yasuo and the worst picks vs Yasuo. This Yasuo counter data is based on matches played by Pros on patch 14.9 and previous ones. It is important to see whether Pros counter picked Yasuo or whether they played as Yasuo.
Champions used by Pros to counter pick Yasuo
Looking at the matches from Pros (see table Pros counter picked Yasuo) we can see that they picked 
Ahri most often to counter pick Yasuo. The matchup Ahri vs Yasuo occured 31 times. Yasuo has 20 wins and 11 losses in this matchup. Learn how to counter pick Ahri to get another perspective on the data.
Lane outcome for Yasuo
When looking at Yasuo counters you will notice that win rates alone are not conclusional. Therefore we provide an overview (see table Lane Outcome) where you can see the lane outcome of Pros who played Yasuo. The lane outcome of Yasuo consists of three outcomes: Win, Loss or Draw. Let's take a look of Yasuo lane and match outcome for specific matchups. Considering the lane outcome and the match outcome of a specific matchup, might enable you to find the right counter for Yasuo.
Conclusion
Analyze the available data and learn how to beat Yasuo. To master Yasuo take also a look on Yasuo builds and runes for Yasuo. Good luck, Summoner!