LONDON: Arsenal manager Arsene Wenger plans to go on the attack as his team bid for revenge in Saturday's Premier League showdown at Manchester United.

Wenger believes Arsenal were too timid as they slumped to a 4-1 aggregate defeat against United in the Champions League semi-finals last season.

But the Gunners have made a flying start to the new campaign and travel to Old Trafford on the back of four successive wins after securing their place in the Champions League group stages with a 3-1 win over Celtic on Wednesday.

That play-off second leg victory followed hot on the heels of crushing Premier League victories over Everton and Portsmouth and Wenger is convinced Arsenal are in the right frame of mind to make amends for that lacklustre European exit against United.

Wenger was encouraged by the way his young team set the tempo during a goalless draw at Old Trafford in the league late last season and will send them out to do the same again on Saturday.

"In the Champions League we were too passive but in the league game we went forward more. It is more mental than tactical," Wenger said.

"I'm happy to go there now because it is the first big, big test. You want always to have a high level of confidence when you go to Old Trafford.

"Beating Celtic is the perfect way to prepare. We are organised and structured to go forward and score. The price we pay is we concede occasionally but as long as we score we don't worry too much.

"Someone told me that our team's average age is 23. We still have things to improve and we want to show we have made a big improvement by the end of the match against Manchester United."

After confounding the critics who wrote off Arsenal as also-rans this season, Wenger knows his team need a strong performance at United to underline their title credentials.

But the French coach may have to do without captain Cesc Fabregas as admitting the Spain midfielder, who missed the Celtic game with a hamstring injury, is not certain to recover in time for the United clash.

Wenger will give Fabregas until the last minute to prove his fitness but he was at least able to rest Robin van Persie against Celtic, while Andrey Arshavin only made a late appearance as a substitute.

"We have to recover quickly physically because Man United didn't play this week," Wenger said.

"Cesc looks to be short for Saturday. Aaron Ramsey has an injury as well, I don't know how serious it is yet. They checked his knee."

Arsenal, who are among the top seeds for Thursday's Champions League group stage draw, took the lead in controversial circumstances when Eduardo dived to win a penalty that he converted himself.

Emmanuel Eboue made it 2-0 after half-time and Arshavin came off the bench to add a third goal before Celtic midfielder before Massimo Donati's stoppage volley reduced the deficit.

While Arsenal can look forward to another season pitting their wits against the cream of Europe, Celtic are now consigned to the far less glamourous Europa League.

But Celtic manager Tony Mowbray believes the experience of taking on a top-class team like Arsenal will stand them in good stead as they try to win the continent's second tier competition.

"There are only four teams in the Premier League with the quality of Arsenal," Mowbray said. "I genuinely believe they could win this competition.

"It could have been a more interesting match if we had got the first goal but when they went ahead they had too much quality.

"I don't think Celtic are in a position to compete with the top four in England at the moment. But we won't play any team as good as this one for the rest of the season in Europe."