How to counter Azir
Let us take a look on how to beat Azir. We will look at champions who are strong against Azir and who are weak against Azir. Use win rate, gold difference and creep score difference at minute 10 to find the best 
Mid champion who counters Azir. You can already win in champion select with the right counters for Azir. If you want to know how to counter Azir then you need to take into account the best picks vs Azir and the worst picks vs Azir. This Azir counter data is based on matches played by Pros on patch 14.10 and previous ones. It is important to see whether Pros counter picked Azir or whether they played as Azir.
Champions used by Pros to counter pick Azir
Looking at the matches from Pros (see table Pros counter picked Azir) we can see that they picked 
Ahri most often to counter pick Azir. The matchup Ahri vs Azir occured 40 times. Azir has 25 wins and 15 losses in this matchup. Learn how to counter pick Ahri to get another perspective on the data.
Lane outcome for Azir
When looking at Azir 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 Azir. The lane outcome of Azir consists of three outcomes: Win, Loss or Draw. Let's take a look of Azir 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 Azir.
Conclusion
Analyze the available data and learn how to beat Azir. To master Azir take also a look on Azir builds and runes for Azir. Good luck, Summoner!