Uefa Champions League, Semi-final first leg Venue:
Old Trafford Date:
Wednesday, 29 April Kick-off:
1945 BST Coverage:
Live commentary on BBC Radio 5 Live, BBC London 94.9 FM, DAB and online plus live text commentary on the BBC Sport website. Also live on Sky
Wenger and Ferguson go head-to-head in Europe for the first time
By Lee Dixon
Match of the Day pundit
The fourth all-English Champions League semi-final in five years sees Manchester United and Arsenal face each other for the first time in the competition.
Both matches promise to produce fireworks, with holders United hoping to reach their third final in 10 years, while 2006 runners-up Arsenal are eager to have another shot at the title.
Who will come out on top - Sir Alex Ferguson's Red Devils or Arsene Wenger's Gunners?
These are the areas I see as key to the outcome of Wednesday's first leg...
CASE FOR THE DEFENCES
United's record of 14 consecutive clean sheets in the Premier League from November to late February and their long unbeaten run was built on a really solid defence.
It isn't just the back four who should take all the plaudits; goalkeeper Edwin van der Sar should be applauded while midfielders such as Michael Carrick, who sweep up in front of the defence, should be given credit too.
Vidic has been a rock for United
United have had a little dip in form of late but that coincided with injuries to the back-line. Now that centre-backs Rio Ferdinand and Nemanja Vidic are back at their imperious best, the team look to be as mean as ever.
They are the best defensive pairing in the league and I actually think Vidic was unlucky not to get the PFA player of the season award.
Arsenal, on the other hand, have been decimated at the back with full-back Gael Clichy and central defender William Gallas out of Wednesday's match.
Arsene Wenger has not been able to field the same back four in quite a long time.
Because Arsenal are weakened in that area, and it's at Old Trafford, Wenger might consider playing the more defensively-minded Abou Diaby or Alex Song in midfield.
So what does that mean for Cesc Fabregas, who has been playing in a more advanced role recently? Does he leave Denilson out? Andrey Arshavin is cup-tied so does Samir Nasri revert to the left flank? Wenger has some big decisions to make.
On Saturday against Tottenham, United's attack was not quite clicking when it was just Dimitar Berbatov and Wayne Rooney up front.
Ferguson made a change and put Carlos Tevez on and all of a sudden they were transformed. Cristiano Ronaldo, who was quiet in the first half, came to life, as did the other three - Tevez sparked something.
Rooney went to the left and that gave him huge freedom where he could cut inside on his right foot, which is what he likes to do.
I really like Rooney. He's such a good player, he can play anywhere and has such enthusiasm.
Cesc Fabregas has been deployed in a more advanced role for Arsenal
I don't for one minute think Ferguson will play all four of them from the start - but he has the luxury of having that option.
Arsenal are pretty useful going forward too, even though Robin van Persie will be absent injured.
It was interesting to see Nasri play in central midfield against Middlesbrough on Sunday, because he normally plays on the left.
It worked a treat though. The Frenchman is a huge talent. You can see he revelled in the space he got in the middle. His passing, movement and the simplicity of his play was really good.
It gave Fabregas the ability to play in a more advanced role, similar to the one Steven Gerrard performs for Liverpool.
Fabregas is such an intelligent player and I think Arsenal get the best out of him when he's allowed to do that and he doesn't have defensive responsibilities.
When a move breaks down for the opposition in midfield, he can split a defence with a great pass.
A GAME OF CHESS?
With it being two English teams playing against each other you'd be tempted to think this will be a Premier League-type encounter.
But it won't. The tempo will be somewhere between a domestic and a Champions League match.
Basically the 90 minutes at Old Trafford is the first half of the tie.
There are away goals to consider so maybe United will be a little bit more cautious because they know this Arsenal team can score from anywhere.
Dixon (left) enjoyed plenty of tussles with United
On the flip side, United know that Arsenal are under-strength in defence - something that Sir Alex would have noticed at the Emirates Stadium on Sunday when he saw Boro test Arsenal several times.
What I do know is that the matches will be blood and thunder - these two teams can't help it when they play each other.
Having played for Arsenal against United in a few of these big matches in the past, I know what goes on in the tunnel - the verbals will be flying as they're about to go out onto the pitch and carry on when the action starts.
FERGIE V WENGER
The managers from both sides thrive on the big-match tension, in the build-up and during the game.
At the end of the season, when the games come thick and fast Ferguson and Wenger come into their own.
Ferguson and Wenger have been rivals for the past 13 years
You almost see Wenger's shoulders widen when he takes on the responsibility of guiding his team on big occasions like this.
There won't be a noticeable change in how the pair go about preparing their teams and what they say to them before the game.
But there will be an air of invincibility around the respective clubs in the belief their teams can win the tie.
The managers and players will push their chests out for these sort of games.
DIFFICULT TO PREDICT
It would be a great achievement for either team to get to the final but they will want to go on and win the Champions League.
It would not surprise me if Arsenal got something from the game at Old Trafford because of their attacking prowess.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.