Chelsea and Barcelona clash at Stamford Bridge with a place in the Champions League final at stake and the tie level following a goalless draw in the Camp Nou.
Barcelona remain slight favourites with online betting experts, with Chelsea less fancied to win at home.
The Blues put up a brave display of defensive resistance last week to keep the much-vaunted Barca attack at bay and were unconcerned by criticism from some quarters over their methods.
Several of the Catalan side complained that Chelsea were overly-physical and were also bitter that two players from each side had been yellow-carded by German referee Wolfgang Stark.
Chelsea showed that such talk means little to them as they brushed Fulham aside 3-1 at the weekend, although head coach Guus Hiddink was concerned by his side's defensive frailties.
He said: "You cannot afford to make the slightest error. I was not happy because we were sloppy in some positions and that's what I didn't like despite a good win.
"If we want to play a little bit for ourselves when we are not fully concentrated, then we give away chances, like we did against Fulham.
"But, if we do that on a higher level, we will be exposed and punished."
Hiddink's defensive woes will be eased by the return from suspension of left-back Ashley Cole and he is likely to be given the task of trying to nullify Lionel Messi, who was expertly marked by Jose Bosingwa in the first leg.
At the weekend Hiddink fielded both Dider Drogba and Nicolas Anelka in attack, but it is debatable whether a 4-4-2 formation will be sued from the start in midweek.
Hiddink will not want to offer Barca any attacking hope, especially following their El Clasico demolition of Real Madrid at the weekend.
Pep Guardiola's side ran riot in the Santiago Bernabeu, winning 6-2 to all but seal the Primera Liga title - with both Messi and Thierry Henry scoring twice.
Carles Puyol was also among the scorers, but he will sit out the Stamford Bridge action due to suspension, having been booked in the first leg after replacing Rafa Marquez, whose season has been ended by a knee injury.
That leaves Barca short of cover at the heart of defence, a predicament which may tempt Hiddink to utilise both Drogba and Anelka, who would have the added motivation of being an ex-Real player.
Both sides will be desperate to reach the final, Chelsea to erase the misery of last year's shootout defeat to Manchester United and Barcelona to try and cement their boast of being the world's biggest club side.
A mark of their total focus came shortly after their success in Madrid, with club president Joan Laporta saying: "I do not want to think about titles because we must respect our rivals and we have a very difficult game coming up in London."
Those comments suggest that this tie will be hard to call right up to the final whistle.