Red Bull motorsports advisor Dr Helmut Marko believes Ferrari was "instinctively wrong" with its decision making in Monaco.
The Austrian has also suggested Charles Leclerc struggles to cope with the pressure applied to the Scuderia.
The Monégasque driver led current championship leader Max Verstappen by 46 points after the first three races.
But after a spin at Imola, a retirement in Spain and then a strategic mix-up in Monaco, Leclerc is nine points adrift of Red Bull's reigning F1 champion.
Asked by Austrian media outlet OE24 why Ferrari had started to struggle, Marko replied: "They are under pressure, which also makes it difficult for Leclerc and he makes mistakes. That's racing.
"In Monaco, we forced Ferrari to react with our pit tactics and they instinctively reacted the wrong way."
Marko - "Anything still possible" in title fight
Verstappen at least managed to extend his lead over Leclerc despite only finishing third in the principality behind team-mate Sergio Perez.
Perez's success, though, means Red Bull has won each of the last four races, as well as the Imola sprint.
On whether the team could begin to think about a championship win, Marko insisted: "[That's] Bullshit. I just did the maths.
"We still have 15 races to go. Even [Mercedes driver George] Russell is only 41 points behind Verstappen. Anything is still possible."