Welcome to the next part of Chelsea's dramatic end to the season. Recovered yet from the foundering of Titanic Hotspur? Then welcome to the unsinkable FC Barcelona. Club historian Rick Glanvill and club statistician Paul Dutton look closely at a fixture with a colourful past.

How fortunate we are to live in these times, to savour such clashes: this is Chelsea's 14th semi-final since the arrival of Roman Abramovich nine years ago. And with Liverpool awaiting in the FA Cup, a world of possibilities has opened up in what could be one of the most epic weeks of the club's 107 years.

It's been said that Chelsea are up against not just a team but a philosophy. While we may not be expecting anyone to die for an idea, we should expect our players to strain every sinew to overcome the exalted Catalans.

Hopefully tonight will not be about a referee's decisions (or lack of them), but there can be no doubt everyone associated with Stamford Bridge still smarts from our last meeting here in 2009. 'Unfinished business' as Frank Lampard described it.

Barcelona also know that they will coming up against a Chelsea side quite unlike anything they encounter on a regular basis. When appraising the Londoners, no Barça player fails to mention Chelsea's physicality, experience and mental toughness.

They must be conscious of the gulf in stature. Their weekend team against Levante would concede an average of seven centimetres per man to the Chelsea side that beat Spurs at Wembley.

It is not just physically where the Catalans know the Blues are a different proposition. As the thrashing of Spurs proved, the rare qualities in Roberto Di Matteo's squad - invisible for part of the season - have re-emerged with almost perfect timing.

If the history books are deemed a credible indicator, the likes of Carlos Puyol and Gerard Pique would do well to keep a close eye on Torres this evening. With seven goals in 10 appearances against the Catalan club, there is no doubt he enjoys playing against them.

Although that has come too late to achieve anything above fourth place in the domestic campaign, tonight's opponents know that strength in the Premier League is more broadly based than in La Liga.

In fact, the gap between Spain's leading two and the next best now stands at 29 points; there are only 26 points between Valencia in third and bottom-placed Racing Santander.

Critics suggest the Primera is in danger of becoming a league lacking jeopardy, which is the product of proper competitiveness and the life-giving sap of any sport.

Unlike some places they visit in their homeland, Puyol and co. will know they have to scrap for everything at the Bridge tonight. And Barça's form away from home has been troublesome at times for Pep Guardiola.

They have lost at Getafe and Osasuna, and surprisingly dropped points at lowly Real Sociedad and Villarreal. Having won all their group stage matches outside Camp Nou the Catalans were put on the back foot by a spirited Leverkusen side at the BayArena, but eventually prevailed 3-1.

At Milan in the quarter-final Barça were held 0-0, the visitors lucky to keep a clean sheet in the second half after dominating the first.

Last season Arsenal beat the Spaniards 2-1 at the Emirates in the knockout rounds by attacking their rearguard, especially in wide areas, and hitting them with two late goals.

The Gunners succumbed of course in the return match, with Barcelona finding the efficiency in front of goal that has sometimes eluded them this season - Chelsea must hope that this is the case at the Bridge.

The only player who has proved clinical all season is Lionel Messi, who struck for the 63rd time in 53 matches at the weekend - just under 40% of their total of 167 this season. He is responsible for nearly half their goals in this year's Champions League and has assisted a further quarter.

For comparison, Chelsea's top performers are Juan Mata, with 12 goals and 16 assists and Frank Lampard, with 16 and eight. The Blues' top scorer in the year's campaign is Didier Drogba with four. The season Ivorian has scored twice in seven games against the Catalans.

In what might be viewed an over-dependence, Messi has contributed more than four times the goals of his best performing Barça teammate, Cesc Fàbregas, and 70 per cent more assists.

The contribution of Fàbregas, who so often appeared hot-headed when playing the Blues with Arsenal, has dipped since the turn of the year, though, with one goal in the Priméra and Champions League this year.

The form of those two, along with contributions from the likes of Pedro and Alexis Sánchez, has meant diminishing returns for some stalwarts this season.

In 2008/09 Andrés Iniesta, the scorer of that heartbreaking equaliser at the Bridge, was on his way to assisting a goal in almost 40% of the matches he played. That has slipped to one in five.

When we last played Barça, Xavi was creating goals in 55% of games; that figure is now down to a third.

We are unbeaten against Barcelona in five matches since our last European defeat at Stamford Bridge in the 2005/06 Round of 16.

Chelsea appeared a team transformed on Sunday at Wembley, Mata, Ramires and of course Drogba putting in their best performances of the season.

They look increasingly liberated by Robbie Di Matteo's 4-2-3-1 and will be buoyed by the scale of victory over an arch rival - the scoreline echoing Watford in 1970.

A win for the Londoners tonight would deal a big psychological blow to the Catalans. They have bowed at this stage of the competition six times and have never overturned a first-leg defeat, not in 1960 against Real, 1975 Leeds, 2000 Valencia, 2002 Real again, nor 2010 Inter.

On that most recent occasion against José Mourinho's side they responded to a 1-3 loss in Milan with a second-leg win at Camp Nou but the 1-0 was not enough.

Their sixth semi-final failure was in 2008 when Manchester United secured a 0-0 draw in Spain before winning 1-0 at Old Trafford - and meeting the Blues in the final in Moscow.

Chelsea are looking for a sixth successive home win in the Champions League having won all five at Stamford Bridge this term, scoring 16 and conceding just two.


- Match preview by chelseafc.com