The Frenchman wants his side to show some more aggression and insists he is not underestimating the challenge posed by Palace

The Gunners got their league campaign off to an awful start with a 2-0 defeat by West Ham at the Emirates Stadium last weekend

Arsenal manager Arsene Wenger has admitted that his side are perhaps lacking the physicality needed to win the Premier League title

Arsene Wenger has told his Arsenal players to stop being so nice and get aggressive if they want to win the Premier League.

The Gunners went into the current campaign full of optimism after enjoying an unbeaten pre-season and defeating Chelsea to win the Community Shield.

However, last weekend they suffered an opening day defeat by West Ham at the Emirates, leading to boos from supporters come the final whistle.

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Arsenal manager Arsene Wenger oversees his side in training at their London Colney ground

Gunners winger Alex Oxlade-Chamberlain (centre) takes on midfielder Francis Coquelin (right) in training

Arsenal striker Olivier Giroud prepares to strike a shot at goal during the club training session on Saturday

And after a lacklustre performance against the Hammers, the Arsenal manager has urged his side to get physical at Selhurst Park on Sunday.

'Sometimes, we are maybe too nice,' said Wenger. 'If you want to say our aggression level last week was not big enough, then I would agree with you.

'It's maybe linked with the fact we were too confident and that we thought we would win the game anyway.

'And maybe you have to look at West Ham as well. They were advanced on the competitive level to us. They had played many games in the Europa League and had started earlier. That might have given them a small advantage.

'But we prepared as we always do, we were focused, but football is football. You have to accept that you can win, lose or draw in every game.

'I know it looks silly today to say that, but it is like that. Even if you play against Division Two, you have to accept that.

'No-one accepts it any more if it is his team, but this is the reality and that is what it is about. Accept that and after give your best to win the game.'

Arsenal midfielders Santi Cazorla (left) and Coquelin (right) are put through their paces in training

Arsenal goalkeeper Petr Cech, signed this summer form Chelsea, throws the ball out of his area

In contrast to Arsenal, Crystal Palace picked up a win during the opening weekend's fixtures as they defeated Norwich 3-1 at Carrow Road.

The victory was the club's 11th in 19 games since Alan Pardew took over eight months ago and Wenger is aware how stern a test his team face.

'Pardew has done a good job at Palace. They will give absolutely everything against us,' Wenger added.

'But we always expect that from our opponents and for them to be like that. That should not be a surprise for us.'

Pardew echoed Wenger's view, warning his opposite number that Palace no longer fear the Premier League's heavyweight clubs.

Pardew believes it is not his side who should be worried ahead of the match but Wenger's after Palace upgraded their pitch, training ground, medical facilities and, most importantly, squad during a busy summer in south-east London.

Alan Pardew has done an impressive job since taking over at Crystal Palace earlier this year

Yohan Cabaye, who nearly joined Arsenal in 2013, is among the new recruits breathing life into Palace.

'There is a belief in our squad that when Arsenal come here we can beat them,' Pardew said. 'I think within this particular group we have a feeling that the type of players we have, we can hurt any team.

'If you can score goals then you can win. Even if they have 65 per cent possession, you can still win the game. We've proven that.

'I don't think the top managers would disagree that the margins are coming down. With our best XI versus their XI, there's not a lot in it. I think they understand that. Let's be honest, on Sunday, I think we're going to see a close encounter here.'