Pirelli F1 boss Mario Isola has conceded to being out-thought by Red Bull and Aston Martin in Baku but has made clear that neither team broke any rules.
Red Bull's Max Verstappen and Aston Martin's Lance Stroll both suffered spectacular left-rear tyre failures during the Azerbaijan Grand Prix due to what Pirelli identified as "a circumferential break on the inner sidewall".
The Italian manufacturer claimed that was "related to the running conditions of the tyre, in spite of the prescribed starting parameters [minimum pressure and maximum blanket temperature] having been followed".
In essence, the two teams - and they were the only two teams to do so in Baku - ran their tyres beyond Pirelli's expected parameters during the race.
Unfortunately for Pirelli, while it can control and monitor the starting pressures and temperatures of all tyres pre-race, it has never been in a position to monitor the parameters it has prescribed during an event, instead taking details recorded by the teams via their own sensors.
This will change next season when the new 18-inch tyres are introduced and a standard sensor will be in operation that will allow Pirelli to monitor the parameters.
With regard to what unfolded in Baku, Isola said: "We assume that running at a certain pressure, a certain camber, with a margin, of course, we run in a condition that is okay for the tyre.
"In this case, we didn't achieve these conditions, not because they were doing something against the regulations, but because they were looking - as usual - for performance and that created a different scenario compared to what we were expecting.
"The different scenario is that mainly the tyres were running at a lower pressure compared to the expectation, and it was not just the lower pressure, there were also other elements in the equation, that created the failure.
"In the regulations, it is not written what are the running pressures you have to respect so I cannot say they were doing something against the regulations in their search of more performance.
"If they respect the starting pressures then at the moment they are complying with the regulations. If the same happens next year when, with a standard sensor, we impose a running pressure, in that case, they will be against the regulations.
"But this is not the case this year, and it is not possible to do that simply because we don't have a sensor that we can rely on measurement.
"That's why each team is looking for performance. They are here racing, not to cruise on track. In looking for performance, if you go with a bit lower pressure you get some performance."
So asked whether he had been out-thought by the teams concerned, Isola replied: "Probably, yes.
"If they were running in a condition that was not expected by us it means that obviously, they found a way to run in a condition that was expected.
"How did they achieve that? You should ask them. What is important for me is that we operate the tyres in the right way."
Questioned as to what the teams did was legal, Isola nodded to affirm that was the case.
He added: "The teams are looking for performance. They are good guys, they have technical departments that are very, very good in trying to find any solution to achieve performance.
"I'm not here to judge if they are more or less clever than Pirelli or the FIA. That's not my role. My job is to give an indication of using the tyres in a way that is safe and correct."
After raising the tyre pressures in Baku by one psi from Friday to Saturday, Isola has suggested that for the tyres to have operated safely on the Red Bull and Aston Martin cars, with hindsight a further 1.5-to-two psi should have been recommended.
From this weekend's French Grand Prix, tyre pressures are being raised for all teams, while a number of other operating procedures will be in place.
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