Lawson was given the full day behind the wheel of the RB21 to bring him up to speed in what was his final outing before the F1 season kicks off in Melbourne in two weeks.
However, rain in the morning curtailed track action and saw the squad change its plans.
Lawson’s progress was furthered hindered by a water pressure leak which resulted in a lengthy stay in the garage.
While outwardly the RB21 looks strikingly similar to the car Red Bull fielded at the end of 2024, significant work has gone on under the bodywork.
That includes a new cooling system, which looks to have struck issues.
Though eventually resolved, it cost Lawson around 30 laps of track running by the end of the day as he ended proceedings having completed just 91 laps.
“I am getting more comfortable in the car, it has been a busy day overall,” Lawson said.
“As part of testing, we were fighting a few teething gremlins with the car through the day, it’s all about just learning about the new car.
“A few of our runs were cut short a little bit and we had to deal with the weather too, which wasn’t great timings for our run plan, as I imagine was the case for most of the pitlane.”
Running was halted around the two-hour mark as the rain, which had been lightly falling for much of the morning, intensified.
Once running resumed, the water pressure issue then saw Lawson back in the garage.
“We decided to do a full day with Liam today, to continue to prepare him ahead of the season,” said Pierre Wache, Red Bull’s technical director.
“Unfortunately, the weather wasn’t great, with some rain at the beginning of the day, so we decided to do a race simulation, to get Liam up to speed with long runs and to check the car for general reliability across race distance.
“In the afternoon, our aim was to understand the car with the C3 compound and the set up options and to also explore the set up of the car in general,” he added.
“We had wanted to get a total insight into the car today, and understand its full direction, but it was also difficult to judge the performance of the car in these conditions and get a lot of the temperature on the tyres.
“But Liam responded well today and his feedback was very close to Max’s. We have good understandings to take into the final day of testing now, with Max at the wheel.”
Though his running was impacted, the laps nonetheless were vital for Lawson ahead of his first full F1 season.
“All this work is extremely valuable going into Melbourne and we feel in a positive place,” he reasoned.
“This is all the most important stuff when it comes to pre-season, this will be the last time I drive the car before Melbourne, to get things right and we are going to take from all of it, to put together the best-balanced car for the first race.”
