Semi-finalist profile: Barcelona

Holders FC Barcelona go in search of back-to-back UEFA Champions League titles and a fourth crown in seven years with in-form Lionel Messi proving unstoppable in Europe.

The UEFA Champions League holders are looking to become the first team to successfully defend their crown since AC Milan won back-to-back titles in 1988/89 and 1989/90. The Azulgrana are in the last four for the fifth consecutive season with Lionel Messi – scorer of 14 goals and the outright holder of the record for most goals in a single UEFA Champions League campaign – the undoubted star of Europe's premier club competition once again.

Story of the season
Josep Guardiola's side did not enjoy the best opening to the defence of their title as they were held at home by seven-time winners Milan in the opening game of the group stage. However, the Catalan club recovered from that setback to top the section ahead of the Serie A side, FC Viktoria Plzeň and FC BATE Borisov. A 10-2 aggregate victory against Bayer 04 Leverkusen followed in the round of 16, while another meeting with Milan came next in the quarter-finals. The Liga team ran out 3-1 aggregate winners after a goalless first leg at San Siro.

Barça are four points adrift of leaders Real Madrid CF as they go in search of a fourth consecutive Liga title, while a Copa del Rey final against Athletic Club awaits at the end of May. As many as three trophies have already been won in 2011/12, though, with the FIFA Club World Cup, UEFA Super Cup, and Spanish Super Cup all safely in the trophy cabinet.

Semi-final pedigree
P12 W6 L6
Last: 2010/11 v Real Madrid CF (2-0 away, 1-1 home)

Record against semi-final opponents
Barcelona and Chelsea have crossed paths ten times in the last 12 years. The first encounter came in the 1999/2000 UEFA Champions League quarter-finals when the Blaugrana advanced thanks to a dramatic extra-time victory at the Camp Nou. The Premier League outfit got their revenge in the last 16 in 2004/05 but were knocked out at the same stage in the following season. In 2007/08 the teams met in the group stage while it was Andrés Iniesta's goal at Stamford Bridge that sealed Barça's place in the Rome showpiece in 2008/09. The balance between the teams in the UEFA Champions League is even with three wins for the Spanish side, four draws and three Chelsea triumphs. The last three encounters have all ended in draws in normal time.

2008/2009 UEFA Champions League semi-final
FC Barcelona 0-0 Chelsea FC
Chelsea FC 1-1 FC Barcelona (agg 1-1, Barcelona win on away goals)

2006/07 UEFA Champions League group stage
Chelsea FC 1-0 FC Barcelona
FC Barcelona 2-2 Chelsea FC

2005/06 UEFA Champions League round of 16
Chelsea FC 1-2 FC Barcelona
FC Barcelona 1-1 Chelsea FC (agg 3-2)

2004/05 UEFA Champions League round of 16
FC Barcelona 2-1 Chelsea FC
Chelsea FC 4-2 FC Barcelona (agg 5-4)

1999/2000 UEFA Champions League quarter-final
Chelsea FC 3-1 FC Barcelona
FC Barcelona 5-1 Chelsea FC (agg 6-4)

1965/66 Inter-Cities Fairs Cup semi-final
Chelsea FC 2-0 FC Barcelona
FC Barcelona 2-0 Chelsea FC (agg 2-2, Barcelona won the play-off 5-0)

Key moment
The holders made their mark on the tournament when traveling to Milan in the group stage. Barça secured top spot in the section with a 3-2 win which saw one of the goalscorers Xavi Hernández produce a footballing exhibition. That win set up a last 16 tie with Bayer 04 Leverkusen, whom Barcelona beat 7-1 in the second leg to send out a warning to their rivals.

Josep Guardiola, Barcelona coach
"We are delighted to be in the semi-finals for the fifth consecutive time.
It's a real achievement and shows the strength of our club. It's the most difficult thing in the world to keep doing it and each time we do, it becomes ever more tricky."

Top scorer
There are few words left to describe Lionel Messi. He has registered 39 goals in the Liga and 14 in the UEFA Champions League to equal José Altafini's haul in a single European campaign and become the youngest player to reach the 50-goal mark in the competition. "We are enjoying this moment," said Messi on his side's run to the semi-finals. "The best thing is that the team is continuing in the same dynamic and winning games which will help us get as far as possible in the Champions League."

Unsung hero
A midfielder by trade, Javier Mascherano has seemlessly provided cover at centre-back when called upon. The Argentinian international has been ever-present in the knockout stages, unselfishly keeping his discipline in defence to allow the attacking prowess of Lionel Messi, Xavi Hernández and Andrés Iniesta to flourish.