'Chelsea must be perfect to beat Barca'
Speaking at a news conference ahead of Wednesday's first leg at Stamford Bridge, Di Matteo, who has revived Chelsea's fortunes after taking over from Andre Villas-Boas, said playing Barca represented the biggest challenge a manager could face.
Chelsea take on Pep Guardiola's European champions after winning nine, drawing two and losing one of their last 12 matches since Di Matteo took charge and he said they were in a buoyant mood after beating Tottenham Hotspur 5-1 in the FA Cup semi-finals on Sunday.
"The spirit in the group is very high, very good and we could not have had a better game than Sunday's to prepare for this game," he said.
"But now we need to play two perfect games to defeat Barcelona and the way we have performed in the last six weeks gives us the belief that we can produce those two perfect games.
"They do not like playing against us. We are two teams who have a lot of respect for each other, but we always give them a lot of problems. Playing Barca gives a manager his biggest tactical challenge."
Chelsea, languishing sixth in the Premier League standings, have not lost to Barcelona the last five times the teams have played.
Since the Spanish side won 2-1 at Stamford Bridge in a round of 16 match in 2006, four matches between them have ended in draws and Chelsea have won once.
The last time they met, though, in the second leg of the Champions League semi-final in 2009 was effectively a defeat for Chelsea when Andres Iniesta's equaliser in the third minute of stoppage time to earn Barcelona a 1-1 draw and seal their place in the final on away goals.
Like Barca, Chelsea have been in the semis six times in the last nine seasons, but unlike their opponents who have gone on to win the Champions League three times in that period, Chelsea have reached only one final and lost it to Manchester United on penalties in Moscow in 2008.
"I wouldn't lie - it is disappointing to have reached so many semi-finals and the final and not win the competition," Chelsea midfielder Frank Lampard said.
"But one of my worst moments was losing the 2009 game. That was worse than any other because of the circumstances, but success comes in football and so does failure and you have to hope that one day we will win the Champions League ourselves."
To do that Chelsea must stop Lionel Messi from adding to the 68 goals he has scored in 59 matches this season, although in six games Messi has yet to score against Chelsea.
He might, however, be able to exploit the hole in the Chelsea defence left by the injured David Luiz.
"That is a big loss for us," said Di Matteo.
Barcelona manager Pep Guardiola told reporters he had huge respect for Chelsea and was impressed by Di Matteo's impact.
"They have the same spirit, the same soul and the same foundation as they had in 2009," Guardiola said. "I admire this generation of players. It is going to be very hard for us. They are very strong, they play the counter-attack well and get to the ball to Didier Drogba who can always score.
"But we are the champions and teams always want to make it very hard for Barcelona."
Barca midfielder Cesc Fabregas, the former Arsenal player, said he was hoping for the same outcome as the last time the teams met in 2009.
"I was playing for Arsenal the night before and we lost in the semi-final to Manchester United, but I was watching the Barcelona match at home the next night with my family and friends and was about to chill out with the Playstation when Iniesta scored. As Barca fans, we were all very happy," Fabregas said.
"The Iniesta goal might be at the back of their minds and make them even more motivated. But so are we, and we are very hard to beat, though it is going to be a very difficult game."