Pirelli's F1 boss has hit back at Fernando Alonso's suspicion that the recent mid-season tyre construction change has hurt Aston Martin.
Alonso admits the Silverstone based team hasn't kept up with car development following its strong start to 2023, but he is concerned that the slump coincided with the debut at Silverstone of new, more robust tyres.
"Since the new tyres came at Silverstone, some teams have struggled more and some teams are now very happy with their car," he said.
"Now, we are behind not only Red Bull but Mercedes, Ferrari and McLaren."
Fellow Spaniard Carlos Sainz, who drives for Ferrari, said when asked about Alonso's claims: "We haven't seen a difference and we haven't felt a difference."
Pirelli boss Mario Isola told Sport1 that he agrees with Sainz.
"Nothing has changed," he said.
"The profile, the rolling radius, the footprint - everything has remained the same."
Isola added that all the drivers were able to test the new tyres in Barcelona prior to the British GP introduction "and nobody felt a difference".
Aston Martin boss Mike Krack isn't blaming Pirelli for the team's recent slump.
"It's a reality check for us," he told DAZN after Alonso and teammate Lance Stroll only just scraped into the points in Hungary.
"We've had a couple of races where we thought it was specific to the track and we thought we could be fast here and we haven't been," Krack added.
"That shows that we are not where we were. Other teams have passed us. This is the ground we have to recover and there is no way to hide that we have to improve the car.
"I think other people have developed faster than us," the German continued. "At the beginning of the season I said that we are competing with very strong teams in the development race and we are not good enough in that."
Krack denied that the situation means Aston Martin should simply write off 2023 and look to design a faster car for next year.
"We don't look at '24," he insisted. "We have to raise our level with this car.
"The regulations are stable and there are always things that can be transferred to next year's car. We really have to work hard to catch up with the cars that are now ahead of us again."
