The Gunners head to Old Trafford for the first leg of their Champions League semi-final in confident mood after extending an unbeaten Barclays Premier League run to 20 matches with a 2-0 win over relegation battlers Middlesbrough, which all but secures another top-four finish.

Despite the absence of leading scorer Robin van Persie, who has a groin problem, injured regular full-back Gael Clichy and the cup-tied Andrey Arshavin on Wednesday night, manager Arsene Wenger has seen his rearguard boosted by the return of goalkeeper Manuel Almunia and centre-half Johan Djourou.

Captain Cesc Fabregas netted both goals to sink Boro, and looks set to again be deployed in a more advanced role against the Red Devils.

Arsenal have already beaten United this season, recording a 2-0 win at Emirates Stadium in November.

Toure sees no reason to believe the Gunners cannot pull off another impressive result.

"For me I am not scared of any team. I know what I have to do when I play," the Ivory Coast centre-half declared.

"There is more pressure on United because they are the team to beat.

"United are the ones who won it last season, but for us we are going there to do the best we can playing free and passing the ball.

"We know when we play football against Manchester United, they struggle a lot."

Toure added: "United are a really good team going forward, but, like us, at the back they have conceded a few goals.

"We have the same type of team - we both like to play, but sometimes you can be caught out at the back.

"The team that will win will be the one which defends the best.

"It is going to be a really big fight."

Toure, 28, is the last remaining regular from Wenger's Invincibles side which went undefeated for the entire 2003/2004 campaign and one of only four players in the current squad who appeared in the 2006 Champions League final defeat to Barcelona.

Now fully focused on his future at Arsenal - having handed in a transfer request during January after a reported training ground bust-up with William Gallas - Toure believes the current squad have the potential to go one better than three seasons ago.

"It will be my second time to play in a Champions League semi-final since I came here, and the Champions League is a massive trophy for us," Toure said.

"We have never won it and we now have the chance. We will go for it - we are not scared."

Toure added: "It is true we lost a player like Thierry Henry, but [Emmanuel] Adebayor is playing really well; we lost a player like Robert Pires, but we have Samir Nasri. All those players have been replaced.

"The good thing about this team is we have a lot of young players who want to show they have the quality.

"I remember that a team like Ajax - nobody was expecting them to win, but they won and had a really young team as well. I think we can do that.

"It is more exciting because it is always really passionate when you see young players playing and you think they have the quality, but sometimes the experience is really important.

"We have been together for a few years now and have made a lot of mistakes.

"However, we are going to learn from those mistakes and we hope not to make any more.

"But at the start of this season, nobody expected us to be where we are.

"We just need to play free, give 100% and see where we end up."

Former United defender Mikael Silvestre is rated as 50/50 to face his old club because of a back spasm.

Youngster Kieran Gibbs is set to fill in again for Gael Clichy, who has a back problem.

The 19-year-old could come up against Cristiano Ronaldo at Old Trafford, but Toure maintained: "Let him play.

"Kieran came in at a really difficult time when we play the big teams and he has showed good character.

"He is intelligent and I think he is going to perform very well on Wednesday."

Toure added: "But it is not only about Gibbs - it is about all the players.

"If we are focused and defend together, then nobody can beat us."