Our final pre-match article in the lead-up to tonight’s big match looks at some of the key performers likely to influence the outcome. It’s a certainty that Barcelona will take to the field in a 4-3-3 but Sir Alex Ferguson’s formation and line-up will undoubtedly shape the proceedings; with individual battles all over the field, just as much will be about stopping the opposition as it will be taking the game to them.

Barcelona

Charles Puyol
While the silky skills of Messi, Xavi, Iniesta et al hog the vast majority of Barcelona headlines, Charles Puyol is fundamental to their resilience at the back. Pep Guardiola’s side have been beaten seven times in all competitions this season and the one common thread in every defeat has been Puyol’s non-involvement.

The club captain has been sidelined for large parts of this season, suffering from knee and hamstring injuries, and, despite Barcelona’s incredible season thus far, it’s still apparent how much his absence has affected the side’s performances. Puyol has played 25 times in all competitions for his club this season, and Barca have won 20 and drawn 5, a win percentage of 80%. They have only conceded 13 goals in those games, which equates to an average of 0.52 goals per game.

Without Puyol, Barcelona have played 34 games, winning 23, drawing 6 and losing 5. The win percentage drops significantly, down to 67%. They shipped 22 goals in those games, an average of 0.65 per game. His return to the heart of Barca’s back-four alongside Gerard Pique will be a significant boost to the favourites, with his pace vital to combat the blistering speed of Javier Hernandez.

Xavi
The heartbeat of the Barcelona side, Xavi has started 10 of his side’s 12 Champions League games this season and has averaged an incredible 130 Touches and 113 Passes per start. It’s interesting to note that Xavi had more Touches (156 and 155) in the two Semi Finals against Real Madrid than in any other European match; Jose Mourinho’s tactics certainly didn’t deprive him of the ball and United look like following suit.

Sir Alex Ferguson has spoken of lessons learned from the two sides’ 2009 Champions League Final, where the side went a goal down and ended chasing the game, suggesting United will be content to sit tight and allow their opponents the lion’s share of possession. The English champions certainly look to have the game to frustrate Barca, conceding just 4 goals in their 12 Champions League matches this season.

Xavi can be expected to see more of the ball than any other play on the pitch tomorrow night and his vision and distribution will be key to unlocking the opposition defence. His Champions League campaign has seen him grab 2 Goals and 2 Assists so far, as he averages 0.9 Shots and 1.91 Key Passes per game, with an outrageous Accuracy of 95%, for a rating of 7.73 per game.

Lionel Messi
Like Xavi, Messi has started 10 of Barca’s Champions League games and the little Argentine has only failed to score or assist in one, the last match, at home to Real Madrid. He’d done the damage by then, though, grabbing both his side’s goals in the 2-0 first leg victory.

Top scorer in this season’s competition with 11 goals, Messi has seen a dip in form of late, having failed to score in his last four games but with a couple of weeks rest since his last appearance, should be fit and raring to go.

In addition to his 11 Goals, Messi has 3 Champions League Assists, and has  4.1 Shots, 1.67 Key Passes and an incredible 5.8 Successful Dribbles per game, for an average of 8.73. With the goals drying up over the last couple of months for both David Villa and Pedro (the pair have scored in 2 of their last 18 and 19 matches respectively) the onus will be on Messi to find the net.

Manchester United

Nemanja Vidic
While injuries have prevented Rio Ferdinand from playing half the club’s Premier League and European matches this term, Vidic has skipped a mere handful of games all season. The big Serb has been outstanding for United at the back; whether he’s partnered Ferdinand, Chris Smalling or Jonny Evans in the heart of defence, Vidic has performed with the same superb level of consistency and he also grabbed 5 goals to help United wrestle the domestic title from Chelsea’s grasp.

Much has been made of United’s defensive record in Europe this season; 4 goals conceded in 12 games is indeed exceptional but their record with and without Vidic further highlights his importance at the back. Vidic has played eight Champions League games this season with his club conceding 2 goals, a record of 1 Against every four matches. Without him, United have played four games and conceded 2 goals, a record of 1 Against every two matches.

With 1.3 Tackles, 2.8 Interceptions, 0.6 Blocked Shots and an outstanding 8.5 Clearances per game in Europe, Vidic has a match rating of 7.28, second best of United’s players. He’ll need to be right at the top of his game tomorrow if his side are to keep Barcelona at bay.

Ji-Sung Park
There’s still a little uncertainty over both United’s starting line-up and shape for tonight’s match but Sir Alex Ferguson tends to call upon the services of Park in the biggest games of all. With Nani and Antonio Valencia vying for a place on the right, Park looks guaranteed to start on the left for United and his battle against Barca right-back Dani Alves will be crucial to the overall outcome.

Alves ended the domestic season with 15 Assists for Barcelona -second only to Messi- as his lung-bursting runs down the flank offers a width missing from his side’s three-man midfield but the vastly under-rated Park has both the energy and tactical nous to nullify the Brazilian’s threat.

The South Korean’s defensive contribution has been crucial in Europe, with 2.5 Tackles and 3.8 Interceptions per game demonstrating how Fergie tends to utilise his talents. Domestically, he’s come into form going forward, too, with 1 Goal, 2 Assists and 1 Man of the Match performance in his last two games.

Wayne Rooney
If United are to stand a chance tomorrow night, much will depend on Rooney’s ability to rise to the occasion. The signs are looking good, though; he has come into a rich vein of form as the tournament has progressed, with 2 Goals and 2 Assists in his last four Champions League games.

A further look at his domestic and European form over the last few months suggests his big game mentality seems to have come to the fore of late; goals against Chelsea, Arsenal, Man City, Schalke and the title-winning goal at Blackburn indicate an added maturity to his game when it matters most.

Playing in the hole behind Javier Hernandez, his Champions League stats show just how Rooney excels in the role; with 2 Key Passes and 2.9 Shots per game, he is both the chief creator and goal threat for United and with 3 Goals and 2 Assists in the competition thus far, has averaged 7.71 per game, his side’s highest-rated player.