And it was another unsavoury episode, coming just 17 days after a Spurs fan was arrested for throwing a banana skin at Pierre Emerick-Aubameyang in the Premier League fixture which the Gunners won 4-2.

Spurs got their revenge for that loss in what was the first game since Manchester United's reported interest in boss Mauricio Pochettino and this result would have strengthened opinion in the north west that he is the man to take over from Jose Mourinho at Old Trafford.

Alli said: "It is what it is. It made the goal a little bit sweeter and the win."

Pochettino, who on Tuesday declined the chance to distance himself from those United rumours, hopes the culprit can be caught but was keen not to tarnish the whole Arsenal fanbase.

"It was lucky that it wasn't a big issue," the Argentinian said. "For me, okay we play a derby and we hate each other in a good way but that is in a bad way when you go to damage some people or an opponent.

"I cannot talk in general because only one stupid person made a mistake. I respect the Arsenal fans, like I respect the professionals from Arsenal and I respect our fans.

"For one you cannot talk about everyone. I hope that Arsenal take responsibility and through the camera they can identify because it wasn't a problem but it can happen to be a big problem."

It was another big game where Alli stepped up as he also set up Son's opener with a great throughball and Pochettino revealed he thrives playing in the pressure games.

"I think I explained before, Dele is very competitive," he said. "He loves to compete. I explained to you that in easy situations he gets bored easily.

"He feels so comfortable when he's in a very competitive space and situation he always gives his best. Yes, that is a quality he has and you cannot buy that in the supermarket of course."

Arsenal had their chances as Aaron Ramsey and Alexandre Lacazette both hit the woodwork, but they were second best.

Mesut Ozil's non-selection was again the main talking point after the game and boss Unai Emery was particularly evasive when asked about his future.

Ozil was not included in the matchday squad and his future at the Emirates Stadium looks bleak.

Emery said: "It was a tactical decision, I thought the players today that are with us, were for us the best for this match.

"We have 24 or 25 players and when they are playing in one or not playing in another it is for me the decision and today it is tactical.

"The focus is to analyse this match and for Saturday, it is a very important match. Tomorrow we are going to train with every player.

"I am thinking about the match on Saturday and not thinking about another situation. Every player is important, I decided he didn't play and it was only a tactical decision."

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