Unai Emery has condemned the incident during Sunday’s north London derby in which a banana skin was thrown from the stands towards the Arsenal striker Pierre-Emerick Aubameyang, saying “nobody accepts” that kind of behaviour.

Four men have been charged by the Metropolitan police over incidents relating to the match at the Emirates Stadium, in which Arsenal beat Tottenham 4-2, while both clubs must answer a Football Association charge after Eric Dier’s equaliser led to a skirmish between their players. The flashpoints overshadowed a dazzling performance from the home team and Emery, who did not speak with Aubameyang after the game, made clear his distaste at the apparent targeting of his player.

“I don’t accept this behaviour, and nobody accepts it,” he said. “I think the [police] are doing their work.”

Among others to express their concern was the England manager, Gareth Southgate. “If proven that there’s any sort of racially motivated incident then it’s unacceptable,” he said. “I think we talk a lot about how much we’ve progressed in terms of dealing with racism in our country but we still have moments like this that disturb you and concern you.”

Six arrests were made on Sunday afternoon and two men were subsequently released without charge. Paul Wright, 41, of Talbot Place, Bexley, was charged with a public order offence and has been bailed to attend Highbury Corner court on 31 December. Averof Panteli, 57, of Borrowdale Drive, Norwich, Charlie Watts, 26, of Goldring Court, St Albans, and Jason Gannon, 36, of Gargery Close, Gravesend, Kent were charged with throwing a missile on to a football pitch. The charges relate to three separate incidents during the match and all three were bailed to attend the same court on 18 December.

Tottenham have said the supporter who threw the banana skin will receive an indefinite ban from attending matches.

Arsenal have confirmed, too, that any fans found guilty of throwing objects from the stands will be given stadium bans. There are suggestions that during the melee that followed Dier’s goal on the half-hour, Dele Alli was struck by a beer can thrown from the crowd.

The clubs will be asked to provide their own explanations of those exchanges after the FA charged them with “failing to ensure that their players conducted themselves in an orderly fashion”. They have until 6pm on 6 December to respond.

In March, Manchester City were fined £50,000 after being found guilty of a similar charge relating to behaviour during their FA Cup defeat by Wigan Athletic.

Emery was more keen to go into detail on football matters, with his transformed Arsenal side looking to extend their unbeaten run in all competitions to 20 games at Manchester United on Wednesday tomorrow. Having convincingly beaten one of their rivals for a top-four spot – enough of a rarity in recent times to be hugely encouraging – Emery believes a repeat performance at Old Trafford is necessary to underline their improvement.

“We know we need to change to get more competitive away [from home],” he said. “I think the team is doing that, but it’s a new challenge because we’re going to play against Manchester United away, and the challenge is bigger than other matches. For us it’s a very exciting match. If we are stronger now we need to [show that] on Wednesday.”

Arsenal’s show of second-half force in the derby owed much to Emery’s introduction of Aaron Ramsey at the interval. The midfielder laid on goals for Aubameyang and Alexandre Lacazette in his most decisive contribution of a season that looks certain to be his last for the club. Contract talks broke down in September and Emery offered no suggestion that the situation would change.

“We need to [see] the difference between his future and his present,” he said. “I think in the last matches his focus [is there]. His focus is positive for us, it helps us. He needs to think about his future, for his family and for him.

“This conversation is not for today. It’s one situation that was closed one or two months ago. At the moment the most important thing is he’s smiling, he has the commitment, the behaviour and the performances like yesterday – that’s the best for him and for us.”

Emery said he did not know whether Mesut Özil, who worked alone on Monday after missing the Spurs game with a back complaint, would make the journey to Manchester.