How to counter Veigar
Let us take a look on how to beat Veigar. We will look at champions who are strong against Veigar and who are weak against Veigar. Use win rate, gold difference and creep score difference at minute 10 to find the best 
Mid champion who counters Veigar. You can already win in champion select with the right counters for Veigar. If you want to know how to counter Veigar then you need to take into account the best picks vs Veigar and the worst picks vs Veigar. This Veigar 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 Veigar or whether they played as Veigar.
Champions used by Pros to counter pick Veigar
Looking at the matches from Pros (see table Pros counter picked Veigar) we can see that they picked 
Ahri most often to counter pick Veigar. The matchup Ahri vs Veigar occured 22 times. Veigar has 6 wins and 16 losses in this matchup. Learn how to counter pick Ahri to get another perspective on the data.
Lane outcome for Veigar
When looking at Veigar 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 Veigar. The lane outcome of Veigar consists of three outcomes: Win, Loss or Draw. Let's take a look of Veigar 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 Veigar.
Conclusion
Analyze the available data and learn how to beat Veigar. To master Veigar take also a look on Veigar builds and runes for Veigar. Good luck, Summoner!