Alexis Sanchez is undoubtedly a very talented player but when it comes to converting penalties his recent record is pretty dismal.
Sanchez decided to ignore protocol and take a penalty during the 4-1 win over Hull City last week despite being behind Santi Cazorla and Theo Walcott in the pecking order.
The Chilean international missed the spot-kick and left head coach Arsene Wenger puzzled over what he had witnessed.
Wenger warned Sanchez not to break the club rules by taking another penalty against Chelsea today according to the Irish Independent.
Sanchez did end up scoring two goals against Hull and has been in impressive form lately but Wenger will be hoping he does not breach the club rules again in the London derby against Chelsea.
A missed penalty could end up being far more costly against a team of the calibre of Chelsea and the Gunners do not exactly have a great record at Stamford Bridge – failing to win their last 10 games away to the Blues.