Hilario in the firing line as Chelsea face up to brilliance of Barcelona

At Stamford Bridge this week, they finally found the saboteur who was trying to undermine Jose Mourinho's team in the days leading up to tonight's match against Barcelona. Despite the club's famous paranoia, it turned out not to be Uefa or David Dein or even the South Central ambulance service NHS Trust - but a fox caught tunnelling his way under the pitch.

The offender in question now languishes in a cage in the groundsman's quarters, although he has not been the first elusive raider to cause problems for the Premiership champions. The last one that Mourinho's team chased after in vain was Lionel Messi in February and he returns tonight with a Barcelona side who have won nine out of 11 games in all competitions this season. Like the intruder licking his paws at Stamford Bridge, the European champions will scent blood.

First the fox, then the Hunt - in this case the Reading striker Stephen, whose challenge on Petr Cech last weekend has caused such upset at Chelsea. Yesterday, Mourinho proved that even given the rich and colourful history between his club and Barcelona over the last two seasons, he is still capable of fostering a controversy capable of overshadowing a match against the greatest team in Europe.

Yesterday was about the minutiae of the treatment given to Cech at the Madejski stadium, which left many of the visitors from Barcelona, more accustomed to hearing tributes to their brilliance, somewhat bemused. They had come to ask about a man called Hilario, the improbably named Portuguese goalkeeper who now carries the burden of shutting out the greatest attacking force in Europe in the highest-profile game of the Champions' League first round.

The 30-year-old had, Mourinho said, been watching DVDs of Barcelona to prepare himself since it became clear on Saturday that, in the absence of Cech and Carlo Cudicini, he would be the man in the firing line. It is hard to imagine the effect on the confidence of the keeper of watching the best of Ronaldinho, Messi and Deco.

He will have been spared the two goals that Barcelona's extravagantly gifted Brazilian scored against Seville in the 3-1 victory at the weekend. A dispute between Seville and Spanish television means that cameras have been banned from covering games involving the club.

"He's no kid," Mourinho said of his new No 1 goalkeeper. "He has played game after game in the first division [in Portugal] and the odd Champions' League game. He is calm and prepared. I don't have any influence on the way he prepares, but I know he has been busy at home.

"He came here knowing he was third choice and third-choice goalkeepers do not normally play. They are normally anonymous."

The anonymous man was at Stamford Bridge yesterday training on a liberally watered pitch alongside another anonymous goalkeeper, Yves Makubu-Makalambay, 20, a Belgian signed three years ago from PSV Eindhoven, who will be on the bench. The problem with this tie is that historically it has claimed a victim. Two years ago it was the Swedish referee Anders Frisk, last season Asier Del Horno - sent off for a foul on Messi in the Stamford Bridge defeat. Hilario will hope to avoid the same fate.

Mourinho paid grudging tribute to Ronaldinho who, he said, even playing at "60 or 70 per cent" of his ability was still a serious threat. Barcelona will be without Samuel Eto'o, who is out for several months with a knee injury. In his place will be Eidur Gudjohnsen, who spent six years at Chelsea and has already scored twice for Barcelona despite having had just two starts, a much more impressive record than Andrei Shevchenko, who has one Premiership goal all season.

The issue of losing Gudjohnsen to a major European rival could become a touchy subject at Chelsea tonight if the Icelander comes back to inflict damage on his old side. Mourinho even went to the trouble of correcting his interpreter when he translated an answer in Spanish as "we miss Gudjohnsen". Mourinho was precise: "We miss all good players."

Gudjohnsen has broken all contact with John Terry and Frank Lampard for the last couple of weeks and does not expect to start calling his former team-mates until after the match is over.

"Barcelona are a world-class team but we are ready for the game," Terry said.

As he walked off the pitch after training, Mourinho stopped to chat with Gianfranco Zola, here as a television pundit. It was a rare moment of calm for the Chelsea manager because, after another week of controversy, he has placed his club back in the eye of a storm on the eve of another big match.

Acting up: Understudy keepers who shone on big stage

Nigel Spink

Aston Villa's first-choice goalkeeper, Jimmy Rimmer, was injured just 10 minutes into the 1982 European Cup final against Bayern Munich. Spink, who had played only once before for Villa, came on and kept a clean sheet as Villa went on to win 1-0.

Les Sealey

While on loan at Manchester United, Sealey must have been as surprised as anyone to be picked for the 1990 FA Cup Final replay against Crystal Palace at Jim Leighton's expense. He made some fine saves as United triumphed 1-0.

Marco Ambrosio

Relatively unknown, Ambrosio was signed as cover by Claudio Ranieri in 2003. He found himself in the spotlight soon enough as both Carlo Cudicini and Neil Sullivan were forced out through injury. Ambrosio played in both legs of Chelsea's 3-2 win over Arsenal in the 2004 Champions' League quarter-final.