Newcastle manager Kevin Keegan launched a stern defence of Joey Barton after the controversial midfielder endured a hot reception on his return to action in today's 3-0 Barclays Premier League defeat at Arsenal. Barton - who was recently released early from a jail sentence following a conviction for assault and affray - is set to face Football Association disciplinary chiefs next week after admitting a charge of violent conduct against former team-mate Ousmane Dabo, and although he had not been expected to feature for the first team, he was drafted into today's squad. Keegan sent the ex-Manchester City man on for the closing minutes of this afternoon's clash with Arsenal - and he was immediately in the thick of the action, with a strong challenge on Gunners winger Samir Nasri. The France international then appeared to trip Barton off the ball, and was cautioned. Keegan had words with both Nasri and also Arsenal captain William Gallas at the final whistle. 'Joey came on, got a good tackle in on Nasri. Then the guy sliced him down. That's what happened and that's what I saw, which is what I was upset about,' the Newcastle manager said. 'I like Nasri very much - he's a player we looked at for a possible signing but you can't do that. 'If it had been the other way round, I wonder what the reaction would be.' Keegan continued: 'I know the referee didn't see it but the linesman did and it should have been a red card. 'I will tell Arsene Wenger the same thing when I see him. 'It wasn't a reckless tackle - it was a good tackle. 'We want to see the good players play, but we want to see good tackles as well. 'Joey has done nothing wrong. I'm concerned about my team, not individual players.' Keegan, though, accepted Arsenal's class came through in the end, with a double from Robin van Persie and Brazil youngster Denilson. 'We came up against a side who had to bounce back from a poor result,' he said. 'We needed a break, which we did not get, like when Nicky Butt's header hit the bar, but there is no denying they are an excellent side and will finish in the top four - the only thing they are fighting for is where they will finish.' Keegan is keen to bring in more new bodies ahead of the transfer window. He said: 'I hope to do more business. We need three players in. 'I have seven very good players and a few who could be in the future, but we need a couple more.' England coach Fabio Capello was watching the match, and saw fit-again Newcastle striker Michael Owen miss a decent chance in the first half. Keegan said: 'That was Michael's first game back to start, but I never liked people telling me who I should pick for England. 'I am definitely happy for him to go if he gets called up.' Arsenal manager Arsene Wenger, meanwhile, hailed his team's 'complete' performance as they continued from the midweek Champions League qualifying win over FC Twente. 'I am very pleased with the performance, both offensively and defensively. It was a complete one, there was great balance in the team, with movement,' he said. 'Apart from at the start of the second half, we were always in control and played the game we love, and showed the way we can play.' The Arsenal manager added: 'The improvement comes from a completely different attitude. 'We showed that against Twente and did it again tonight. 'The Fulham match had come at the start of the season after difficult games, including one away in the Champions League and maybe we were not ready mentally.' Dutchman Van Persie - who endured an injury-plagued campaign last season - had to come off in the second half with an ankle problem, which is understood not to be serious. 'We do not know yet. He has to have an X-ray on his ankle. Hopefully nothing is broken,' said Wenger. 'He is the link between the midfield and the strikers, which is very important in the game we want to play. 'Robin showed that when he is good shape physically, he is a very important player for us.' Wenger will continue his quest to bring in a new midfielder ahead of Monday's midnight deadline. He said: 'We are trying to buy new players, But the problem is always first of all, the availability and also the fact that it's finding players who are better or at least as good as the ones we already have.' On the incident involving Barton and Nasri, Wenger diplomatically noted: 'I was not surprised by the reaction of the fans - I have been involved in the game long enough not to be surprised by anything. 'Nasri clipped Barton and there was a little incident between them, but he was booked and rightly so.'