Arsene Wenger has confirmed that Alexis Sanchez broke rank to take Arsenal's penalty against Queens Park Rangers that the Chilean subsequently missed.
Sanchez was fouled by former Arsenal defender Armand Traore in the first-half the encounter at the Emirates Stadium and then proceeded to step up ahead of Santi Cazorla in order to take the spot-kick.
But the former Barcelona player saw his limp effort easily saved by Rob Green in the opposition goal, wasting a glorious opportunity for Arsenal to break the deadlock in the Boxing Day clash.
Cazorla had taken and scored each of Arsenal's previous two penalties, against Stoke City and Newcastle, having assumed duties in the absence of Mikel Arteta and, said Wenger, allowed Sanchez to take his place vs QPR contrary to orders.
"I think Santi is a nice guy and let [Sanchez] take it. Honestly, he is not No 1 on the penalty list, that's true," Wenger told reporters after the game.
"Arteta is our No 1 taker and at the moment Cazorla is No 1."
Fortunately for Sanchez he was able to get on the scoresheet soon after - heading a Kieran Gibbs cross into the net at the back post - to break into double-figures in his maiden Premier League season.
Olivier Giroud was later sent off for Arsenal to provide some tense moments, but Tomas Rosicky killed the game off before Charlie Austin scored a late consolation for the visitors.