Jaime Alguersuari reacted angrily on Thursday after journalists expressed doubt about the health of his Formula One career.
The Spaniard had kept cool in the official FIA press conference at Valencia, when reporters asked him about rumours Daniel Ricciardo could replace him at Toro Rosso before the end of the season.
"At the time it was just one more rumour among all the thousands of others.
"But at the end of the press conference I realised for the first time that I'm sick and bored of all the nonsense.
"Apparently the rumour has more weight than the comments of (team chiefs) Franz Tost or Helmut Marko. I'm not worried about my future.
"I am sure of myself and feel the appreciation and the respect of the whole Red Bull organisation," insisted Alguersuari, 21.
I realised for the first time that I'm sick and bored of all the nonsense
"If someone wants to know more about my future, or Buemi's or Ricciardo's, there is only one authority -- Helmut Marko. Any other source is not valid.
"It's stupid and I'm bored of it," he concluded.