A troubled day for McLaren on Thursday saw the squad record just 50 laps across eight hours of running during F1 pre-season testing in Bahrain.

The opening day started with a change of plans for the squad as Lando Norris was drafted in to replace an unwell Daniel Ricciardo.

However, the Brit recorded the second fewest laps of anyone for the day – only Pietro Fittipaldi for Haas, who completed only the afternoon session, completed less.

“We had quite a few issues today with the car,” Norris said at the conclusion of Thursday’s running.

“We took a long time to figure it out and it limited us quite a bit to the amount of laps we wanted to do.

“Bit frustrating because, especially here being so different to Barcelona, we wanted to try and understand as much as we could, and the differences, and how the car’s working here on a much bumper track.”

Chief among the issues experienced by McLaren related to braking performance, especially on long runs.

“Temperatures and stuff didn’t allow us to do long runs,” Norris explained.

“Things we are trying to fix [over] the next few days, it’s not going to be an easy fix.”

While McLaren arguably experienced the worst of it on Thursday, it wasn’t the only team to face issues.

Mercedes and AlphaTauri clearly struggled with porpoising, while locked brakes were prevalent throughout the field.

That is expected to be something of a feature this season, with the heavier wheels less prone to unlock easily.

At McLaren, the running it did get was used to continue learning the nuances of the MCL36.

“The car’s still sensitive to the wind,” Norris explained.

“We found it out just because Barcelona’s not windy, so it’s kind of good that we understood that it’s still there.

“It’s a lot hotter today than what it was in Barcelona, how the tyres are working on the cars, a lot bumpier so how the cars performing over the bumps and the compromises you’ve got to make with the setup are very different.

“All these things are trick today, and we have to try and understand and figure out.”

The second day of testing is currently underway in Bahrain, with fans able to follow along via the Mobil 1 Live Updates.