CHAMPIONS LEAGUE LIVE: Barcelona v Real Madrid - follow the action from the Nou Camp as it happens

The millions of fans who tuned in to last week's first leg at the Bernabeu expecting fireworks of the football variety from two teams teeming with attacking talent were left bitterly disappointed by an encounter that was explosive for all the wrong reasons. From both sides' unpalatable histrionics toJose Mourinho's unsavoury accusations, those who had been promised a footballing feast prior to kick-off were still feeling famished after 90 fiery minutes.

The fallout from 'El Clashico' has been widespread and varied but, among the reams of subjectivity, one objective fact stands out: Barcelona are 2-0 up and playing at home in the second leg. Buried in Mourinho's post-match vitriol and character assassination of referees the continent over was at least one sensible statement: "The return game is mission impossible."

The Catalans unquestionably have one foot in the final at Wembley, where a rematch of the 2009 showpiece with Manchester United will likely await. Pep Guardiola has lost just four of 37 Champions League games in charge of Barca and he can even afford to lose this one by a one-goal margin and advance. What Barca must be wary of, though, is the prospect of being drawn into a bloodbath at Camp Nou and risking players being suspended for the final. The first leg boiled over on several occasions and it is paramount for the Primera Division leaders that Messi and co concentrate on dazzling their rivals and dominating possession.

A 'throw-caution-to-the-wind' approach does not appear to be in Mourinho's armoury but it is surely the only solution if Real are to become the first team in Champions League history to overturn a 2-0 first-leg home defeat to progress. 'Parking the bus' may have worked for Inter last year but to salvage a reputation that, despite the Copa del Rey triumph, has taken a pummelling of late, it appears Mourinho's only option will be to liberate the wealth of offensive talent at his disposal. That playing this way could see his side succumb to the sort of embarrassment suffered in this season's first El Clasico - when Barca ran riot to thump Los Blancos 5-0 - is a risk the Portuguese may just have to take.

Without the suspended Pepe to protect the back four, Real will likely rely on Sami Khedira and Xabi Alonso to drop deeper than they were required to last week, leaving room for an extra attack-minded player. Karim Benzema is one option, but Gonzalo Higuain - who has been ushered slowly back into action - may be worth a punt as Real desperately search for goals. The absence of the experienced Sergio Ramoswill be a blow, though it is softened by the return of the equally seasoned Ricardo Carvalho.

Little can be read into Real and Barca's respective defeats to Real Zaragoza and Real Sociedad in La Liga at the weekend, with both clubs inevitably focusing their attention on the second leg, but defeat for either side at Camp Nou will certainly be scrutinised more carefully. Expect sparks to fly.

Real Madrid player to watch - Angel Di Maria. Last month's Copa del Rey triumph was Real's only victory over Barcelona in their past eight meetings and the architect of the winning goal was skilful Argentina winger Di Maria. His superb cross for Cristano Ronaldo was tempered by a later sending off but the former Benfica star showed that Barca could indeed be unlocked. His fearless dribbling and ability to deliver from wide positions, coupled with Dani Alves' defensive shortcomings, could hold the key for Real again at Camp Nou.

Barcelona player to watch - Sergio Busquets. The image of Busquets peeking through his eyes in last year's Champions League semi-final second leg, having feigned a blow to the face to get Thiago Motta sent off, is probably pinned on a novelty dartboard in Jose Mourinho's office. But like him or loathe him, Busquets is a vital cog in the Barca machine. With Real needing to go for the jugular, the Spain midfielder will be required to stifle Messrs Ronaldo and Ozil, a task he has managed with aplomb already this season.

Key Battle: Ricardo Carvalho v Lionel Messi. While Jose Mourinho v referee Frank De Bleeckere could yet emerge as an ugly duel, Carvalho's attempts to shackle Messi will be much more important in determining the result. A calming presence, superb in the air and an accomplished ball-player, Carvalho has gone some way towards solving Real's age-old problem of defensive frailty. But he and centre-back partner Raul Albiol will be tested to the full by the most devastating player in world football, whether Cristiano Ronaldo likes it or not. Messi has been at his irrepressible best this season and his tally of 52 goals doesn't even paint a full picture as he has also contributed 22 assists to Barca's cause. He is already third on Barca's list of all-time goalscorers and another salvo against their rivals would see him further cement his place in the pantheon.

Trivia: The last time Real won by two goals in the away leg of a Champions League knockout tie was against Barcelona in 2002.

Stats: Lionel Messi conceded more fouls than any other Barcelona player in the first leg at the Bernabeu and the second most in the game behind Real's Lassana Diarra.