Red Bull's Max Verstappen reported a solid day's work at the Circuit de Barcelona-Catalunya, as Formula 1 reconvened for the second four-day pre-season test.
However the RB14 did trigger a red flag late in the afternoon, after stopping at turn 1.
Verstappen reported that the stoppage was caused by a minor problem that was quickly rectified. He was able to get back out on track for the final quarter of an hour.
“It was a good day," he said after the chequered flag called time on the day's activity,
"We had one small battery problem so we had to change that. It always takes a little time, but afterwards it was all good again.
“The most important thing was to get a lot of laps under our belt, see how the car was behaving," he said. "So we managed to do that."
Red Bull's Head of Race Engineering, Guillaume Rocquelin, provided a little more detail about the causes behind the glitch
"We took the decision to do some shakedown tests. And the result was small electrical problem," he explained.
"We lost an hour as we had to change the battery but it was a calculated risk and we learned something as a result."
Despite the interruption, Verstappen finished the day with a best time of 1:20.649s on medium tyres, after completing 130 laps on Tuesday.
The only driver to beat that tally was Ferrari's Sebastian Vettel on 168 laps, although the combined distance covered by Valtteri Bottas and Lewis Hamilton in the Mercedes reached 176 laps.
But Verstappen isn't comparing himself to any of his rivals at this point, and is instead focussed on his own progress.
“We did a lot of laps, that was very important to get the mileage on the car,” he said. "[It felt] all good
"But we still don’t know what the others are doing," he added. "We have to wait for Melbourne and see how good - or bad - we are."
Verstappen teased possible upgrades to come on the car before that first race of the season. "You have to keep your eyes open," was all he woudl reveal to reporters trackside.
"The car is definitely faster than last year, so that is positive," he said. However, the resurfacing work at the track made it difficult to say exactly where the car had improved.
"It really changes the whole car, the whole way of driving, also with the new tyres," he said of the new tarmac.