Arsenal's Bacary Sagna, left, vies for the ball with Manchester United's Javier Hernandez, during their English Premier League (Photo: AP)
The Gunners are set for a sixth successive season without a trophy after a 3-1 defeat away to Stoke on Sunday ended their already fading Premier League title hopes.
Arsenal's weakness at defending setpieces was exposed again when an unmarked Kenwyne Jones bundled in Stoke's opening goal and Sagna said such errors would have to be eliminated if the north London club , who beat champions-elect Manchester United 1-0 last time out, were to win the title next season.
"We are too nice. We have to fight a bit more. We have to push them as much as they push us and be a bit more killer," full-back Sagna told Arsenal TV Online.
"We are not defending as well as we have to and against big players like Stoke have, it is very difficult.
"We have to put in performances week after week and fight even more.
"We didn't give enough. We didn't play as we can and that is what happens when you don't give the maximum - you get beaten everywhere."
Arsenal manager Arsene Wenger has been urged to abandon his usual policy and make big-money signings in the close season in order to bolster the Gunners' shaky defence.
But Sagna insisted said the current squad could provide the necessary improvement. "It can be put right on the training ground because it is in our mind," the 28-year-old France international said.
"We know we are very good players, but sometimes we have to fight a bit more."
Arsenal currently lead Manchester City by five points in the race for automatic Champions League qualification, but the FA Cup finalists could reduce that down to just two if they beat Tottenham at Eastlands on Tuesday.
This season has seeen Arsenal lose the English League Cup final to top-flight rivals Birmingham while also suffering early exits from both the Champions League and FA Cup, at the hands of Barcelona and Manchester United respectively.
However, Wenger insisted: "Many would like to be in the Champions League but it is not enough, certainly, but the season has not been for nothing.
"It could have been a lot more, but you can see it is the toughest league in the world and we were very close, but we have to add what we miss," the Frenchman added.