Laporta, who officially returns as Barcelona president on July 1 after acting president Rafa Yuste's interim tenure, spoke at the Koeman Cup on Friday.
His remarks were pointed and sustained, addressing Pérez's press conference last week in which the Real Madrid president — announcing he would seek re-election — made claims about the Caso Negreira and alleged that Barcelona had cost Madrid league titles.
Laporta was blunt about the motivation he saw behind the appearance.
"I think it was grotesque, but it had a strategy. Seeking to divert attention from two years of winning nothing, and this has them very worried. They somehow have to justify the unjustifiable, and the best way is to stoke the flames and throw everything they can at Barcelona. This we will not allow. The club will react."
He also deployed what has become one of his favourite framings of the rivalry.
"We are concerned about Barça. Barça is my vocation and I am strong enough to push this institution forward. We are consolidating the economic recovery, we are going to finish the stadium and we will have a very competitive team. The rest... I see that when they have barcelonitis, things tend to go well for us. We are with and for Barça."
Barcelonitis — Laporta's term for Madrid's preoccupation with Barcelona — has become a recurring feature of his press interactions and resonates strongly with the club's support. His characterisation of Pérez's conference as strategic rather than spontaneous aligns with the position Barcelona's legal team announced in the hours after it took place, when the club said they were studying legal action in response to Pérez's comments about the Caso Negreira.
Laporta will again lead a club that has just won its second consecutive La Liga title under Hansi Flick, with a Champions League final against Paris Saint-Germain in Budapest on May 30 also on the horizon.