Hansi Flick has rapidly moulded a ragged Barcelona into a potent threat to Europe’s elite and the visit of his former Bayern Munich side in the Champions League on Wednesday is their first acid test.The Catalans have not reached the semi-finals of the competition since 2019 and were humiliatingly thrashed 8-2 by the German giants in 2020, when Flick was at the helm in Bavaria.Five-time Champions League winners Barcelona lifted the trophy most recently in 2015 and failing to thrive on the road to this season’s Munich final would mark a decade in the doldrums since.Flick’s Barcelona have started La Liga in stunning fashion with nine victories and just one defeat in 10 matches, while scoring 33 goals.The league leaders delivered a stylish display of attacking football to rack up a 5-1 win over Sevilla on Sunday ahead of the Bayern Munich clash and Saturday’s La Liga Clasico battle against Real Madrid.Barcelona thrashed Young Boys 5-0 earlier in October in the Champions League after an opening 2-1 defeat at Monaco.Flick, who led Bayern to a sextuple in 2020, has swiftly transformed a Barcelona side who won nothing last season under Xavi Hernandez into a swashbuckling force despite injuries to several key players.Gavi made his comeback from a severe knee injury on Sunday, while Frenkie de Jong, Ronald Araujo, Andreas Christensen, Marc-Andre ter Stegen and others face long spells on the sidelines or are only just returning. READ ALSO: Fraudster impersonates Lewandowski’s agent to scam Barcelona £1m Perhaps the most crucial difference has been former Bayern striker Robert Lewandowski’s return to form.Flick has backed the Polish striker to the hilt despite his struggles last season and the 36-year-old has responded with 14