Red Bull team chief Christian Horner said his championship-winning Formula One outfit has had to revise its pit-stop routine because rivals were copying their moves. Horner said on Wednesday that Ferrari had followed the Red Bull stopping strategy in last weekend\'s Spanish Grand Prix - until they decided to make a \'dummy call\' to throw them. \"Pit-stops are all part of the game and Ferrari\'s only way to beat Mark (Webber) was to cover him in the pit-stops,\" Horner explained. \"They saw something we were doing that was giving away when we were going to stop. \"And then they would call Fernando (Alonso) in - because it couldn\'t be coincidence that he just happened to stop every time that we called Mark in! \"That is within the regulations, of course. \"In the end, we made a dummy call. Fernando came in and Mark stayed out, but unfortunately by that time, he had lost so much time to Jenson (Button) and Lewis (Hamilton) that a podium finish was not possible. \"But it is all part of the game and all part of being a team sport. I think it is only like a dummy pass in a rugby match or any other sporting activity.\" After the race at the Circuit de Catalunya, Red Bull\'s motor sport advisor Helmut Marko had claimed that Ferrari must have been hacking into Red Bull\'s team radio, but this was not supported by anyone else. Horner said he has no doubts that Ferrari used fair means to discover when Red Bull were preparing to pit -- which is why they have reacted to ensure it will not happen again in Monte Carlo this weekend. \"That is why we have changed our procedures this weekend,\" he said. \"I don\'t know if mechanics were putting their hands in their pockets at the wrong time, or it was someone picking a tyre up. But anyway, we have changed our procedures this weekend to be less transparent.\"