"It's a lie, it's a disgrace, and I'm angry with you," said Robson as he walked out.
The former England manager was responding to reports that squad members and the club president, Jose Luis Nunez, were involved in choosing who should play.
"It's not the players, it's not the president, or the doctor, it's nobody but me," Robson said in English, before repeating himself in Spanish for the benefit of the assembled journalists.
Newspaper reports had claimed strikers Hristo Stoichkov and Juan Pizzi had begun warming up without being told to by Robson when Barcelona went 3-0 down to Atletico before their spectacular 5-4 Spanish Cup win last week.
Several Spanish newspapers carried reports on Monday which quoted Robson as thanking Nunez for recommending some changes during the 1-0 league win over Logrones.
Robson's relationship with the press has steadily deteriorated since his arrival at the Nou Camp. Problems on the field - Barcelona trail the league leaders Real Madrid by nine points - have been aggravated by Robson's limited knowledge of Spanish.
Many journalists and supporters are thought to be nostalgic for the era of ex-coach Johan Cruyff, who left Barcelona last May after eight seasons in charge. Legal action by Cruyff against Nunez for slander began yesterday, with statements from witnesses connected to the club.
In a heated press conference the day after firing the former World Cup star, Nunez accused the Dutchman of accepting money to support rival candidates to the club presidency and of favouring his striker son, Jordi, over other players.Reuse content