With Arsenal leading 1-0 early in the second half thanks to Aaron Ramsey’s opener, the Gunners midfielder was given his marching orders after bringing down Harry Kane and being shown a second yellow card at White Hart Lane.
Spurs scored twice in quick succession to take the lead shortly after his dismissal, but 10-man Arsenal earned a point thanks to Alexis Sanchez’s late goal.
Speaking to Arsenal Player after the game, 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 spirt is great and we fought until the end.”
Coquelin will now serve a one-game suspension and will miss Tuesday’s FA Cup replay at Hull City.
Saturday’s draw left Arsenal third in the Premier League table and three points behind Spurs heading into the final nine games of the season.
The Gunners are now eight points behind leaders Leicester City, who beat Watford 1-0 at Vicarage Road on Saturday evening.
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