Red Bull team principal Christian Horner has bemoaned a "horrible day" for Max Verstappen after the reigning F1 champion could only muster just five timed laps in Miami Grand Prix practice.
The Dutchman glanced the wall early in FP1 at the exit of turn 16, which marks the end of a narrow, twisty technical section of the otherwise fast and flowing Miami International Autodrome, with his team changing the gearbox as a precaution.
Work overflowed into the second session and after missing the first half of the hour, Verstappen suffered an issue on his first lap out of the garage that prevented him from turning left.
In the final sector, as he was forced to grind to a halt on the racing line just to get around left-handers, flames started to flicker from the rear brakes and continued until Verstappen he reached the pits.
Speaking to Sky Sports F1 to assess his driver's struggles, Horner said: "He has had a horrible day.
"We had an issue this morning so as a precaution we changed the gearbox and one of the coolers, he has driven out the pit-lane and had a hydraulic issue which has unfortunately caused some damage to the rear brakes there.
"He got a few laps in, I think he had five timed laps which were all competitive but thankfully with the red flags he has not lost too much but it is frustrating not to have that track time."
Red Bull "relying heavily" on Perez data
Whilst Verstappen was consigned to the sidelines, Perez shrugged off a spin at turn eight to finish third quickest for the day and collect vital information for his team.
"Checo has had a good session there and long-runs, short-runs, we have got a lot of info from him," explained Horner.
"So we will be relying heavily on all of that knowledge and that will influence the set-up direction Max takes tomorrow as well so that side of the garage had a good run."