Helmut Marko accused Sergio Perez of already being in "summer break mode" before the Hungarian Grand Prix.
The Mexican is third in the drivers' standings and just five points behind Charles Leclerc. Earlier in the season, it looked as though he would be a main rival to team-mate Max Verstappen after winning the Monaco Grand Prix.
But things have not gone so well for Perez since, and he is now 85 points adrift of the other Red Bull racer. That has clearly left long-serving team adviser Marko unimpressed, as he took aim at the 32-year-old for his recent performances and attitude.
"He is too far behind Max Verstappen at the moment," he told Sky Sport Germany after qualifying in Hungary. "He was struggling in all the practice sessions, so we will have to sit down with each other. The summer break hasn't started yet, but he already seems to be in that mode.
"We need to speak to him and he needs to stick to Verstappen's set-ups and be there from first practice. If you're a second slower in first free practice, you don't catch up. We saw that in some races last year as well. We managed to eradicate that then, so we have to make sure we counter that again."
Verstappen started the race 10th after an engine issue in Q3, but went on to win the race comfortably. Perez was just one place behind him on the grid, but could only move up to fifth by the time he crossed the finish line.
Still, he seemed pretty pleased with himself and the team after the race. "It is good to go into the summer break strongly," said the Mexican. "After qualifying it was looking like it could have been a poor weekend for us but we recovered some good points, and it was great fun to have the Mercedes and Ferraris racing up there with us.
"It was quite a tricky race, particularly towards the end, when the conditions changed and especially during the virtual safety car which meant everyone got cold tyres. Overall, we were a little unlucky with the VSC because we were potentially going to get Carlos and George and I felt we would have got a lot closer to them towards the end.
"I felt a lot stronger in the final stint and with a few more laps I think I could have been on the podium with Max. It was a great race though and very fun at times. It was a fantastic recovery for the team today and it was great to see Max get the win."
