Arsene Wenger has praised the increased strength of European football, while acknowledging that Champions League qualification is no longer guaranteed for a fourth-place Premier League finish.
Arsenal, who finished fourth in the English top-flight last season, consequently had to overcome a strong Udinese side in August to secure their qualification for the Group Stage of this season's Champions League, highlighting the increase in quality.
"Looking at the quality in Europe, it is going up, for any English team it is difficult. I have felt that for a few years now," Wenger told The Mirror.
"Where it [Champions League qualification from fourth place] was just a formality before, now it is not.
"With Udinese we had two hard games, they are a top team in Serie A."
After being knocked out of the tournament by AC Milan the London side are now focused on the closing stages of their domestic league campaign and closing in on Tottenham.
"I try to do my best and just know that I am ready to fight.
"At the moment for Tottenham, it [third place] is still in their hands. It will be down to consistency.
"We have difficult games, they have difficult games and I think we have to make sure first that the fourth spot is there."
Chelsea are the only English side left in this season’s Champions League but trail 3-1 to Napoli after their first leg.
Wenger said: "You look at the results of Man City and Man United at home this season and you would think that they were the two teams who would manage to go through easily. It is difficult.
"Judging on this season we [English teams] are not [on top], they [the rest of Europe] have caught up.
"Maybe because in England every championship game is a complete commitment, we suffer a bit more in the decisive Champions League games.
"This season did not go well. Maybe the clubs have to up the quality of their game."
Former Southampton midfielder Alex Oxlade-Chamberlain impressed against AC Milan last week and his manager admits he is struggling to control the hype surrounding the player.
"His feet are on the ground, but we have to manage him in a responsible way as well," Wenger said.
"The problem when you have a talented player like that is that everybody wants him to play every single game. If you do that then he will be injured.
"I am a great admirer, but it is difficult to slow the enthusiasm down on the expectation level."