In a historic twist starring Jose Mourinho, Barcelona gained revenge after a 28-year wait, brushing aside Catalan neighbours CE Europa 4-1 in a friendly.
The two sides had not met since the 1998 Catalan Cup final, when Europa, nicknamed "Escapulats", sprang a stunning surprise and lifted the trophy at Barcelona's expense on penalties. Leading the Catalan side from the bench that day was Mourinho himself, then working as assistant to coach Louis van Gaal.
Twenty-eight years on from that defeat, Barcelona restored their reputation in the best possible way. They dominated from start to finish and settled matters with goals from Ibrahim Diarra, Hector Fort, Ibrima Toncara and Alex Gonzalez, with Flavio grabbing Europa's only reply.
Flick's side, packed with academy players, outclassed their opponents to secure the 4-1 win. The scoreline barely mattered, though. The point was to bank early experience, give players minutes and gauge their physical progress.
Indeed, Flick named a lineup bearing little resemblance to the one that will contest the official season, with a host of reserve team players and even youngsters from the youth ranks.
La Masia prospect Hamza Abdelkarim stole the spotlight on his first appearance with the first team, turning in a fine display and staking his claim among the young faces.
Barcelona took control from the off. Brian Farinas opened the scoring in the 30th minute before Abdelkarim added a second two minutes later. Europa hit back to narrow the gap in the 42nd minute, and the first half closed with Barcelona leading 2-1.
After the break, the Catalan side sharpened up in attack, adding two more to settle the match at 4-1.
Gil Fernandez caught the eye with a superb display in midfield, while Ibrima Toncara also shone brightly.
Ter Stegen played the whole second half, despite his loan to Ajax being close to completion. Ademi, meanwhile, was left out of the squad altogether.
This win is an encouraging start for Hansi Flick, who leaned heavily on youth in the absence of most of his international stars.