Watch the below video and consider your ruling, along with the reasoning, before opening the analysis.
The attacking player dispossesses the defending player of the ball and makes a run towards goal. The defender, knowing he will not be able to stop the attacker, holds the players shirt and makes an illegal tackle. The defending player denies his opponent an obvious goal scoring opportunity by pulling his shirt. This can be considered denying an obvious goal scoring opportunity and the defending player should be given a red card with a direct free kick awarded.