A minute's silence was observed before kick-off for the death of Jorge Messi, Lionel Messi's father, as Barcelona took part in the inaugural Friuli Venezia Giulia Cup, an unusual triangular format the club hadn't experienced in more than two decades, involving two 45-minute matches against Nottingham Forest and hosts Udinese.
Flick fielded a mixed side of first-team players and academy prospects, with Hamza Abdelkarim again leading the line after starting against Europa and Birmingham, while Fermín López and Raphinha made their first pre-season appearances of the summer.
Nottingham Forest, freshly beaten by Udinese in the tournament opener and rebuilding under new head coach Oliver Glasner following last season's 16th-place finish, started the brighter of the two sides, with Igor Jesus and Morgan Gibbs-White both going close before Brian Fariñas struck the woodwork for Barcelona.
The decisive moment came deep into stoppage time, when Nikola Milenković's handball inside the area gave Barcelona a penalty, which Raphinha converted with composure to snatch the win.
Speaking afterwards, Flick addressed the club's busy summer of departures.
"We've had to make decisions that weren't easy. I've advised them. This is the situation. Every team has to make changes. You have to leave space for the young players," he said.
Asked specifically about Ronald Araújo's impending Liverpool loan, the head coach was warm about the defender despite their tactical mismatch.
"He's a great guy and a fantastic player. But the way he plays is different to what I set up. He's powerful, with pace... it's a shame. It's been difficult because I haven't included him as much as I would have liked. He's been affected by mistakes made in the past.
"We've talked. I saw him well today, happy, I wish him all the best. Changes are normal in life and in football. There's a lot of noise around it. We know what we want. We want to improve the team. We're calm. Next week a lot of players will arrive. This pre-season isn't normal, there's little time."
On Ferran Torres's reported move towards PSG, Flick was notably guarded.
"I respect the players' holidays and I don't know anything. I haven't spoken to him. Today I was focused on the triangular."
He was considerably more effusive discussing two of the players who did feature, praising the impact of Raphinha and Fermín López despite their limited training time.
"He's been training with us for 10 days, and Fermín a bit longer. I see them well. Raphinha is the most important player for me, because of his intensity, he's one of the captains, he fights for the team..."