As the most keenly awaited fixture of the Champions League second round has drawn closer, the Chelsea and Barcelona camps have been picking at the scab that conceals the wounds from their last meeting. It will not take much to get the bad blood flowing again.

The problems began in the build-up to last season's second-round tie between the clubs with Mourinho giving an interview in which he stated that, though the former Holland midfielder Frank Rijkaard had been a player of the highest calibre, the Barcelona coach was unworthy of comparison with himself as a manager.

That claim rankled but Rijkaard was all the more affronted by what he considered as disrespectful Mourinho's naming of the Barcelona team as well as Chelsea's before the match.

"Usually when people talk, it's a sign that they're not very calm," he said.

The following evening any semblance of calmness was to be swept away in a storm of controversy. Chelsea staff alleged they had seen Rijkaard enter the dressing room of the Swedish referee Anders Frisk at half-time.

When the Chelsea striker Didier Drogba was sent off in the second half, Mourinho's anger reached boiling point.

Rumours swirled around the Camp Nou after the match that Chelsea's goalkeeping coach, Silvinho Louro, had come to blows with members of Barcelona's backroom staff.

Then emerged word that Rijkaard's assistant, Henk Ten Cate, had kicked Mourinho in the rump, prompting the Sun headline "Kicked up the Barca".

The truth of the reports of a fracas was never established but Mourinho, furious at the claims that the referee had consorted with Rijkaard, boycotted the obligatory interviews, and the source of his ire was made clear.

Rijkaard and Frisk denied that any such meeting had taken place and Uefa, the European governing body, leapt to the official's defence, angered that a manager might impugn the impartiality of a referee.

Mourinho was accused by Uefa of "poisoning" the game after Frisk brought what was anyway his final season in refereeing to a close three months early following alleged death threats received from England. Mourinho was fined and given a two-match touchline ban even though Uefa admitted Rijkaard had approached the referee at half-time.

In the second leg Chelsea overturned a 2-1 first-leg deficit to win the tie 5-4 on aggregate. There were more scuffles in the tunnel, mainly involving the Barcelona striker Samuel Eto'o, who accused a Chelsea steward of racially abusing him.

Eto'o's anger still lingers. "Mourinho has a way of expressing himself which is not particularly pleasant," the Cameroon international was quoted as saying in the French sports daily L'Equipe.

"I told him so to his face in the tunnel after the match. I went up to him and said, 'I know [ you think] you are a great person and a great coach but in truth you are just a shit.'"

Mourinho and Rijkaard will renew hostilities tomorrow night, with Eto'o and Drogba both presumably having points to prove.

Though Frisk will not be a protagonist in the latest chapter of this saga, the official whom Uefa's referees' committee elected yesterday, Terje Hauge of Norway, will be required to ensure the match passes without any controversy.

Whether that will be possible is another question. Rijkaard's antipathy towards Mourinho appeared to be simmering when he was quoted yesterday making derogatory comments about the Portuguese's preferred style of play.

"Without a doubt it is easier to produce a defensive soccer team because it does not need you to have talent for it, but simply to be well organised," said Rijkaard. "The last time we failed in covering tasks but that does not mean that we have to play in the defensive way Chelsea do." It is unlikely that Mourinho will allow such comments to pass unanswered.