The Spanish side are favourites to defend their trophy, led by the brilliant Argentina international Lionel Messi and with a certain former Arsenal skipper Thierry Henry now also among their star-studded squad.
However, results in the last round proved European pedigrees can count for little over what is essentially 180 minutes of cup football.
Indeed, Liverpool - five-time winners and who reached the final in both 2005 and 2007 - failed to make it out of the group stages, while Barcelona's Spanish rivals Real Madrid, who had spent millions bringing in Kaka and Cristiano Ronaldo, were humbled by French champions Lyon.
Confident: Fabregas insists Arsenal can knock out Barcelona
Fabregas believes Arsenal can take heart from such achievements as they aim to upset the formbook and progress through to the semi-finals for a second successive season.
'The last round of the Champions League was interesting and it shows you can never underestimate any opponents in this competition,' Fabregas said.
'It should be a warning that any team left in can beat anyone else - even if the reputation is lower maybe than Real Madrid, Chelsea or Liverpool, they can still win.'
The Arsenal skipper is relishing the chance to take on his boyhood club, where he played in the same youth team as Messi and Gerard Pique.
'I know they will be two exiting games,' said the Spain international, who left the Nou Camp to join Arsenal when still only a 16-year-old in September 2003.
'We will, of course, give everything, and you know if you want to win the competition, you have to be ready to play anyone.'
Fearsome opponent: Messi
The clash against the European champions has captured the imagination of the Gunners fans, eager for a slice of revenge after losing the 2006 Champions League final against the Spaniards.
Arsene Wenger will, though, make sure his players are focused on the job in hand when Barcelona come to Emirates Stadium for the first leg on Wednesday night.
'When you get into the quarter-finals, you know you will face good teams, and you respect what your opponents have done,' said the Arsenal manager.
'But competition is about what you do yourselves. We will make sure we have our belief and focus right.'
Russian playmaker Andrey Arshavin was ineligible for last season's competition, when the Gunners reached the semi-finals before they were beaten by Manchester United.
The former Zenit St Petersburg midfielder is in no doubt if each and every one of the Arsenal players produce a performance, there is no reason why they should not progress.
'Everyone is looking forward to this game, and it will be tough, especially away,' Arshavin told Arsenal TV Online.
'At this moment, Barcelona are playing very well and Lionel Messi is in good form, but we must play our own game, and see what will happens.
'We have to be focussed on our game - if we do not give a good performance, we will never beat them.
'If we can show our best game, when everyone is together, we can beat them.'
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