The Gunners finished fourth in the Premier League last season, slipping one spot from the year before. However, the Ivorian insists that the league is becoming tighter at the top, with the 'big six' – Manchester United, Manchester City, Arsenal, Chelsea, Tottenham and Liverpool – all competing for the title.
"For the past decade it has been the same teams but now the money comes in at a team like Man City and they spend a lot to deliver," he told the club's official website.
"Tottenham as well are making ground, they have got some great players too.
"You have to fight and that's what makes the English league so good to watch because there is competition. We know there are favourites but there are outside teams who can make trouble."
The 24-year-old, who had a number of standout performances last season, was regarded as one of the few bright spots ina disappointing season for the club.
"As players we have to be on our toes but I think Arsenal is still on top because even if I look at last season, the problem before was that we couldn't beat the biggest teams but last season we didn't have any problem with that.
"So I think we just need to get those little things right and it will be great for us."
Djourou started 22 games for Arsenal last season, scoring one goal.