Arsene Wenger confirmed key defender Shkodran Mustafi will miss Arsenal’s crucial forthcoming fixtures after he picked up a ‘bad’ hamstring strain during the 3-1 win over Stoke City at The Emirates.

The Frenchman confirmed the German centre half – whose influence has been one of the cornerstones of the Gunners’ good form this term – will be out for a minimum of 21 days – ruling him out of the festive period as well as vital games this week against Everton at Goodison Park and Manchester City at The Etihad.

Referring to the injury also ruling him out of the Boxing Day fixture against West Brom he said: “He will now have a nice Christmas [as he will not be playing].

“It is a bad hamstring strain. I don’t know how it happened.

The former Valencia player’s injury apart it was a good day for Wenger’s team as goals from Theo Walcott, Mesut Ozil and Alex Iwobi sealed the game after Charlie Adam put the Potters 1-0 up from a first half penalty following a challenge by Granit Xhaka on Joe Allen.

However Wenger was adamant referee Lee Mason should not have awarded the spot-kick.

He said: “We have given a lot over the last few days at West Ham and at Basle and we had a hesitant start. But we found the resources to win the game.

“We had have three penalties given against us here this season that weren’t penalties including this one – and despite that we came back and won the game – in the last four away games Stoke didn’t lose including at Manchester United.

“It was not a penalty. There was no foul. No foul at all. I don’t think it was a penalty.”

Stoke made a bright start but appeared to fade in confidence and endeavour after Walcott’s equaliser late in the first half and Arsenal created numerous chances in the second 45 minutes.

Wenger explained: “The key at 1-0 down was not to bring my frustrations into the game, and for the team to keep their nerves and their composure – and that’s what we did. we kept passing the ball and didn’t panic.

“Through some positive results we have created a momentum that gives us strength now and we have belief in our game – it’s good we are in the fight [for the title].

“Psychologically it’s difficult to win when everyone expects you to win – but that’s what we did today.

“When you analyse our season last year we did very well at home against the top five teams but we dropped points against teams placed between fifth and 12th at home – mid-table teams.

“Our challenge this year is of course to do well against the top teams, but also against teams like Stoke as well.”

Referring to a goal and an assist coming from the bench today in the form of Iwobi’s clinical finish and Hector Bellerin’s cross for the first goal, Wenger added: “We have top quality on the bench now. There is not one player you can question.”