After a strangely defensive match at the Nou Camp in which they seemed to adopt a catenaccio mindset, United will look to get back to their usual attacking approach. At the Nou Camp, United appeared content to hope for something on the counter-attack often leaving Cristiano Ronaldo isolated alone up front with Rooney defending on the right side of midfield. They also played a cagey game at the weekend against Premier League title rivals Chelsea but suffered a 2-1 defeat, which saw Chelsea move level at the top with two games to go. More importantly, Nemanja Vidic was kneed in the face and Wayne Rooney picked up another knock on his already injured hip. Both missed traiing yesterday and are doubtful for today’s match.

Barcelona’s faint hopes of a Primera Liga title vanished with a dreadful performance against the league’s current form side Deportivo La Coruna that saw them lose 2-0. It was clear that Rijkaard had the Champions League on his mind as Samuel Eto`o, Lionel Messi and Xavi were all rested while Deco, Victor Valdes and Eric Abidal started the match on the bench.

Lineups and Tactics:
With Rooney doubtful, Tevez will likely start up front though it might be as part of a front pairing with Cristiano Ronaldo. Ronaldo had success playing as a centre-forward against Roma and Ferguson might try that tactic again. The back four will take a similar shape as to the one deployed at the Nou Camp. Owen Hargreaves could start at right-back but it would not shock me if Gary Neville were given a start, which would be his 100th Champions League appearance. Neville is short on match fitness though so it is most likely to be Hargreaves, which will see Anderson get a start in midfield. Ryan Giggs played a ful match at the weekend so it is likely to be a fresher set of legs put out today — look for either Park or Nani to start on the left. It is almost certain that Wes Brown will replace Vidic as Rio Ferdinand’s partner in the centre.

Sir Alex Ferguson has stated that his side will be more aggressive in the second leg and look to make use of the home atmosphere.

Possible Starting XI (4-4-2): Van der Sar — Hargreaves, Brown, Ferdinand, Evra, — Anderson, Scholes, Carrick, Nani — Tevez, Ronaldo

Barcelona boss Frank Rijkaard has pledged to stay true to his side’s attacking philosophy but that will be tempered with a good amount of slow, careful buildup. Rijkaard is attack-minded but he is far from naive. He realizes that United are likely to come barreling out and his team will have to sit a bit deeper during the opening minutes to soak up the early pressure. Overall, Barca will hope they can dominate possession much the same as they did at the Nou Camp. Barcelona are not adept at sitting back and defending in numbers while waiting to counter-attack. How they deal with the early pressure likely to come from United will be a large factor in determining how this match turns out. We’ve seen other sides wilt under the pressure at Old Trafford, most recently Roma last season, but I think Barcelona are too experienced for that to happen. They’ve been to this stage of the competition several times in the last number of years and as this is their last chance for some hardware this season, I’d be shocked if we saw anything less than a strong effort from the Catalans.

Barcelona will welcome back captain Carles Puyol, who is making his 75th CL appearance, they may have a worry in the middle of the park. If their holding midfielder Yaya Toure cannot play (he has picked up an ankle problem) that will be a major blow for Barcelona as they do not have a direct replacement available. Rafa Marquez could slot into that role but is suspended and utility man Edmilson is just returning from injury though he will take the place of youngster Giovani dos Santos in Tuesday’s 18-man squad. Edmilson can do the job but is going to be short on match fitness and sharpness so if he starts that may be an advantage for Manchester United. It will also be interesting to see whether Rijkaard retains Andrés Iniesta on the left or gives Thierry Henry the chance to start against his old rvials. Considering the chances he created in his brief cameo in the first leg, I’d give the nod to Henry.

Possible Starting XI (4-3-3): Valdés — Zambrotta, Puyol, Milito, Abidal — Deco, Edmilson, Xavi — Eto’o, Messi, Henry

Key Matchups:
Paul Scholes v Xavi
There are so many similarities between these two players and I’d have to say these are my two favourites from these squads. Other players may grab more headlines with flashy goals but these two are the ones that provide the platform for those goals. They are smart distributors of the ball, they can get forward and nick a goal but they can also provide protection for their back four. Scholes excelled in Barcelona when he was asked to take on defensive duties while Xavi was key in helping Barcelona dominate possession. He moved he ball effectively and jumped forward to support the attack on a number of occassions. The roles will need to reverse this week if United are to be successful. If Scholes cannot support the attacks from his deeper position in the centre, it will be tough for United to sustain possession and to control the tempo of the match.

Patrice Evra v Lionel Messi
I highlighted this matchup in the first leg and I think it is going to be key again. Messi’s pace and ability to get to the endline and cut ball back for his teammates is a big part of the Barcelona attack. However, he does like to cut to the inside and take on defenders, which is what makes his that much more dangerous. Despite getting schooled a time or two, I thought Patrice Evra did a decent job of marking Messi. If he can match or improve on his performance from last week, United will be in good shape. Adding to his task, is that for United to have more possession and put pressure on the Barcelona backline, Evra must go forward more than he did in the Nou Camp. Without the supporting runs from the fullbacks, United’s attacks will fizzle much like they did a week ago.

One would have to say that Barcelona have the easier path at the moment. A draw sees Barcelona through and only a win will put Manchester United into the final. Working in United’s favour is the fact that the hold the Champions League record for straight home victories and Sir Alex Ferguson has talked about the pride his players place in that record as they aim to extend the winning streak to 12 games.

Since the knockout phase started this season, 14 ties have required extra time. Could this be 15? I don’t think so but the game will be close and I could see United scoring later in the second half and advancing 1-0 on yet another timely goal from Tevez. The worst scenario for United is an early goal from Barcelona that allows them to relax and play at a relaxed tempo.