Serie A champions Juventus travel to the Camp Nou on Tuesday to take on the Catalan side they eliminated in the quarter-finals of the European competition last season.
But first up is modest but consistent Chievo Verona, whose players earn a combined 18 million euros ($21.6m) annually compared to the 164 million euros ($197m) pocketed by Juventus’ squad.
And Chievo coach Rolando Maran has no illusions about the task awaiting in Turin.
“When you go there you know that you will suffer, but it is a beautiful suffering, one which makes you grow and them suffer a bit too,” said Maran, whose side snatched a point in Turin two years ago.
Germany midfielder Sami Khedira is back for the six-time title holders who are looking to stay ahead of the pack at home with a third win in as many games after Cagliari and Genoa.
But Allegri will have to do without defender Giorgio Chiellini, who picked up a calf injury playing for Italy, with Andrea Barazgli also sidelined after Azzurri duty against Spain and Israel and forward Paulo Dybala recovering after Argentina qualifiers.
Juventus could line up with the defensive partnership of Daniele Rugani and Mehdi Benatia, though new German signing Benedikt Howedes is a possibility, as Benatia played two games with the Moroccan team.
New arrival Mattia De Sciglio also wants to impress his former Milan coach Allegri.
“It was important for me to be reunited with Allegri, who showed great confidence in me at Milan,” said the defender.
“Saturday’s game will not be easy, Chievo are very organised. We will have to go with the right mind-set to take home three points, and only after can we think about Barcelona.”
Also preparing for European curtain raisers are AS Roma who travel to Sampdoria on Saturday before hosting Atletico Madrid on Tuesday.
AS Roma are midtable after two games — falling 3-1 at home against Inter Milan last weekend — with unbeaten Sampdoria among the leading group.
Napoli look for a third win at Bologna before their long journey to Shakhtar Donetsk in Ukraine on Wednesday.
De Sciglio’s former team AC Milan travel south to Lazio with city rivals Inter hosting SPAL on Sunday.