LONDON (REUTERS) - Arsenal manager Arsene Wenger is concerned his flying team may lose some of their intensity as their "big month" continues with a trip to Old Trafford on Sunday.

The Premier League leaders face champions Manchester United hot on the heels of beating Liverpool 2-0 at the Emirates and overcoming Borussia Dortmund 1-0 away in the Champions League, with midfielder Aaron Ramsey especially on fire.

Arsenal's victory over Liverpool last weekend put them five points clear at the top for their biggest lead since February 2008. The Gunners have lost only once in the league this season, a 3-1 opening day home defeat by Aston Villa.

"We passed (the test against Liverpool) in a convincing way," Wenger told Arsenal Player. "The focus of the team and the togetherness you could feel from the outside, they refused to lose this game and you could feel that from the start.

"You could not have predicted that after the first game (Villa) so let's enjoy it, take a lot of encouragement from it and continue to develop as a team," Wenger added.

"And as well be cautious and be on our toes, because we changed it in an emphatic way so let's make sure we continue to grow and not think 'OK let's have a little breather'."

The tables have turned since a beleaguered Arsenal were humiliated 8-2 by United, which included a Wayne Rooney hat-trick, in August 2011 in a low point for Wenger.

Arsenal, who have not won silverware since 2005, are now eight points ahead of a United side still adapting to manager David Moyes' methods following Alex Ferguson's retirement after winning his 13th Premier League title last season.

"At the moment, with 10 games played, you can say 25 per cent of the season (has gone). You see the first tendencies and trends but it's still not settled," Wenger said.

"By the end of November you will have a clearer idea."