Scrutiny has no time for reason or patience in European football. When a club sends a world-class centre-back to a domestic rival? That type of move will prompt skepticism at the first sign of trouble.
How much do Juve miss the poise of Leonardo Bonucci?
"Tonight was our first night together, so it wasn't a matter of serenity," Allegri said. "Tomorrow will begin the official preparations toward the road of our game in Rome on the 13th of August.
"There's a lot of preparation to be done."
He's right. Just seven weeks have passed since Juve were beaten 4-1 by Real Madrid in the Champions League final, and the Bianconeri have another three weeks before they face Lazio in the Supercoppa Italiana.
The squad that has gathered in the United States hardly had a chance to train together before testing themselves against Barca's high-powered attack. While the 82,104 in attendance made for quite the spectacle, the reality of the occasion was evident. At this stage in pre-season, sheer talent will trump a more tactically-dependent side.
Neymar and Lionel Messi may have carved apart an experimental Juve line-up before half-time, but the Old Lady found their rhythm in the second half. Aside from halving the deficit with an emphatic header, Giorgio Chiellini brought much-needed stability to the back-line. Adding the likes of Miralem Pjanic, Paulo Dybala and Gonzalo Higuain to the attack also kept Barca on their heels.
"Considering it was the first time that we got together as a group the team played well," Allegri said. "It's always difficult to get together and play a match that's important right off the bat."
Bonucci, of course, is a defender of the highest class. His anticipation, physicality and distribution make him the complete package, and a reported fee of €40 million feels like a bargain for AC Milan.
That said, Juve's defensive discipline can't be credited to just one player. The Bianconeri conceded 27 goals in 38 matches en route to the Serie A title last season, and just three in 12 Champions League fixtures before the defeat in Cardiff.
If Bonucci's relationship with Juve began to crumble after seven seasons at the club, so be it. Under Allegri, Juve have operated as an impenetrable unit. They close space, slowly but surely suffocating opposition attackers. The personnel and formations evolve, but the results remain the same.
In Chiellini, Andrea Barzagli, Mehdi Benatia and 22-year-old Daniele Rugani, Juve still boast quality in central defence. The exit of right-back Dani Alves was swiftly addressed by the signing of Mattia De Sciglio, with Stephan Lichtsteiner still a factor as well.
Retaining the services of left-back Alex Sandro — who reportedly is considering a renewal amid interest from Chelsea — would be a coup. Gianluigi Buffon remains an ever-dependable anchor in goal, with the newly-signed Wojciech Szczesny a decent backup option.
And Juve could still move to replace Bonucci in the transfer market. But for now? It's far too early to panic.
"I feel comfortable with the defence," Allegri said. "If there is a possibility with the market to strengthen our club, fantastic. If not, we're good the way we are."