Arsenal manager Arsene Wenger has hit out at Manchester United defender Paddy McNair after the Northern Irishman's late tackle in the 2-1 win at the Emirates Stadium left Jack Wilshere facing a lengthy spell out injured.
Wilshere will see a specialist next week to learn the full extent of the ankle ligament damage suffered on Saturday 22 November after McNair's late tackle forced the England midfielder off after 55 minutes.
Though the injury is not to the same right ankle that Wilshere underwent surgery on in 2011 and 2013, Wenger is concerned the blow could lead to a similarly extensive period out.
The flying tackle from McNair, 19, left Wilshere is significant pain and Wenger has criticised the challenge from the United youngster which the Arsenal boss labels as a "bad foul".
"It doesn't look good but the tackle approached him from the side," he explained. "I watched it again he moved the ball away just too much, then when he dived to make the pass McNair dived in and took him from the back and the side.
"When you see the picture is it very bad. I don't think it was a tackle with a desire to hurt. I think he went for the ball, but it was a late tackle and a tackle that a young player can do. But it was a bad foul.
"There is no bone damage we knew that away straight after the game, but it's ligament damage. The extension of how much it is we will know next week. It's the other ankle, the good ankle.
"It's so sad because he just came back and in the big games he has that personality. He shows he is not scared to play and scared to want the ball always.
"He refuses to lose the ball and is ready to put his body on the line. It is part of his game as well.
"He struggled for a while with his right ankle, but he found his mobility back. I hope it will not be surgery but he will be few weeks but I don't think after mentally it will be too much."
Wenger will hope that victory over the Champions League opponents Borussia Dortmund on Wednesday 26 November can improve a winless three-match run going back to the collapse against Anderlecht in the club's last group match.
The recent run has drawn criticism from minority shareholder Alisher Usmanov, who says Wenger must begin to learn from his mistakes or risk dragging Arsenal further into the mire.
Responding to being asked whether the comments were fair, Wenger said: "I don't know anymore what is fair.
"I know what happens after you win a big game. I am just disappointed that at the moment there is life in our team and there is quality in our team. We know where we failed on Saturday.
"I am very positive about this team I think it is one of the best teams I have had in a long time.
"You really think you can do 30 years in my job and not take criticism? If I couldn't take criticism I wouldn't be here. You learn to adapt and take a distance with that is right.
"I am just frustrated and sad that people who love this club are not getting the results they deserve. The players put so much energy in and don't get rewarded."