Arsenal defender Per Mertesacker rapped teammate Francis Coquelin after his dismissal in their 2-2 draw at Tottenham.
The Frenchman was shown red with over 35 minutes of the game still to play.
Mertesacker said: “I think we need to be more disciplined in those occasions.
“There was no danger, he was at the sideline as well. It took us 15 minutes to cope with that, being one man down, but after we played fantastically and could have scored a third one I think.
“We had couple of good breaks and how the team responded after 15 minutes was great. In between it took us a bit but in the heat of the game it is difficult. Overall, the spirit is great and we fought until the end.”