Richard Williams says that while Jose Mourinho may be a star, the weakness of his squad is that no one else shines as brightly

Speaking strictly in terms of statistics, the odds against Chelsea going through to the quarter-finals of the Champions League were 20 to 1 against. Of 245 sides to have lost by a score of 2-1 at home in the first leg of a tie since the founding of the European Cup half a century ago, 95 per cent had failed to recover their position in the return. That was the measure of the task facing Jose Mourinho last night.

One thing of which you could be sure was that he had been burning the midnight oil over the tactical plan with which he hoped to rescue his team's place in this season's competition. The need to score two goals while holding Barcelona's brilliant trio of attackers at bay would have tested the combined ingenuity of Alexander the Great, Carl von Clausewitz and Vo Nguyen Giap, but if there was one contemporary football general capable of meeting the challenge, you fancied it would be the Portuguese controversialist.

The return of William Gallas in place of the suspended Asier Del Horno gave a more secure look to the left flank of his defence, but it was in attack that the significant change took place. Damien Duff was added to the midfield, while Arjen Robben moved up to partner Didier Drogba in a repeat of the formation with which, for a while, Chelsea managed to keep Barcelona fully occupied after Del Horno's first-half dismissal a fortnight earlier.

It almost worked twice in the opening 20 minutes last night when Drogba spurned two clear chances to give Chelsea the lead, first from Joe Cole's diagonal cross and then from Arjen Robben's free-kick. Having failed to get his head to the first, he headed the second straight into the arms of Victor Valdes.

Mourinho must have been chewing lumps out of his notebook when those two chances went begging. Having spent the last few days demonstrating that he would not know the moral high ground if you gave him a lift there in a helicopter, he was trying to take the opportunity to re-emphasise his elevated standing among the present generation of coaches. Had Drogba capitalised on either of those openings, it would have set the match ablaze.

The coach had made his first appearance of the evening 40 minutes before the kick-off, standing alone and striking a confident pose five yards inside the touchline as he watched his goalkeepers warm up. As he had promised, he was soaking up the cat-calls of the few thousand Catalans scattered around the vertiginous grandstands. When Chelsea's players made their appearance, however, the home fans demonstrated that Mourinho had failed in exhausting their derision.

The announcement of the Chelsea team was the cue for the erection of a wall of sound that threatened the eardrums. As Mourinho settled into his seat in the dugout, he could not have attracted so many photographers had he been a movie starlet removing her top on the beach at Cannes.

Yes, Mourinho is a star. But the weakness of his squad may yet turn out to be the absence of performers whose light shines as brightly as his. Rigorous organisation can be enough to win things, as he proved in the Champions League with Porto two years ago, but the method has a limited shelf life and an even more limited appeal to neutrals, who will prefer intuitive spontaneity.

There could hardly be a greater contrast of approaches than the one existing between Chelsea and Barcelona, which is one of the reasons - besides the combustible relationship between their coaches - why their meetings have proved so compelling.

Last night the presence of four Brazilian-born players in Barcelona's starting line-up meant every time a Chelsea pass went astray, that was the last Mourinho's players would see of the ball for a couple of minutes.

Ronaldinho, after a quietly influential performance at Stamford Bridge, was clearly in the mood to turn the return leg into a more explicit display of his unique gifts. Before Lionel Messi succumbed to an injury in the 25 minute, the two of them had been weaving wonderful patterns between the Chelsea defenders. For a time Ronaldinho seemed to want to turn the match into an exposition of the art of the back-heel, as if out of some deeply felt desire to demolish once and for all the suggestion that coaches might be the ones who really decide matches.

With an hour gone, and his side virtually becalmed, the Chelsea manager made one of his double substitutions. A year ago we would have expected a miracle to occur. Now we know that Mourinho's gambles sometimes work, and sometimes fall flat.

A stroke of individual genius was what Chelsea needed at this point, but there is room for only one genius at Chelsea, and he sits on the bench, wearing a suit and tie.