Arsene Wenger concedes that Real Madrid and Barcelona have raced ahead of all other clubs this season, revealing his fear that Arsenal are being left behind by Europe's big spenders.

Wenger reinforced his own squad on transfer deadline day by signing Park Chu-Young, Per Mertesacker, Andre Santos, Yossi Benayoun and Mikel Arteta. However, the Gunners' tactician believes they are some way off the pacesetters ahead of their Champions League opener away to Borussia Dortmund.

"I believe that this season, I see two teams that are above the rest - Real Madrid and Barcelona - and the rest have to catch up during the season," Wenger told The Guardian. "So for us, it's a new start because we are a new squad. What is at stake during the group stage for us is to show that we can go through.

"We are in our 14th season in the Champions League group phase and what has changed is that the competition inside England has become bigger among the top teams. It is as difficult to win the Champions League because a team that wins the Premier League is in the Champions League final almost every year.

"Outside the country, Barca and Real Madrid have much more financial power than they had 14 years ago because they have individualised their TV rights. So they, at the moment, with teams like Man City and Chelsea can take who they want."

Wenger cautioned that even Europe's richest clubs will soon feel the pinch, though, predicting a "financial crisis" to grip the continent, impacting upon the expenditure of all clubs.

"I believe that Europe overall, as a unit, is going towards a massive crisis, which nobody really expects now. I am convinced that Europe will go into a huge financial crisis within the next three weeks or three months and maybe that will put everything into perspective again.

"Football is not untouchable. We live with people going to the stadiums as well and from advertising from people who buy products. All our income could be a little bit under threat in the next few months. Football is not only about money. We believe in ourselves that we can compete with them but it's as simple as this."

The Arsenal manager says that his charges are confident after their Premier League win over Swansea at the weekend, but would not be drawn on the Gunners' chances of Champions League glory ahead of their game with Dortmund at Signal Iduna Park.

"We have not had a particularly strong start in the league. We have had five players coming in [just before the transfer deadline] and nobody knows how good they will be.

"I wouldn't rule it out but it's too early to speak about winning it [the Champions League]. Saying that would raise a lot of scepticism about the team and I don't think anyone would believe it. But we have to do as well as we can and we have to form a team in the next two months. It's too early to have that kind of ambition."