Max Verstappen chose to go his own way on Friday when he rejected using soft tyres to embark on a long run on mediums in fear of rain in second practice at the Bahrain Grand Prix in Malaysia.
His decision resulted in him finishing fourth fastest behind Ferrari's Charles Leclerc and his Red Bull teammate Isack Hadjar, but he gained valuable data and insight into conditions that were close to those expected for Sunday's race.
"I think we had a decent start, but it's tricky," said the four-time world champion, who won the last Formula One race at the Sepang International Circuit in 2017 and topped the times on softs in opening practice.
"The track is really hot. A lot of degradation, so a lot of things to figure out, but it's been positive.
"I wanted to do a long run in case there was some rain coming in. It's hard to know if we made progress, but there are a lot of things to try and to understand."
The abrasive conditions on the low-grip circuit in sweltering conditions – with a track temperature of more than 60C – have led to forecasts of a three-stop race on Sunday.
McLaren's Oscar Piastri, who was sixth, said he had been impressed by Red Bull's opening day pace.
"It looks pretty close among the top four teams," he said.
"I think Red Bull have looked very strong through the day. Mercedes as well have looked strong, at points, and obviously Ferrari were pretty good.
"Everyone’s kind of had their turn being reasonably competitive. I think we’re maybe a tiny step behind, but we made a lot of progress from FP1.
"Hopefully, we can keep that trend going – and we’ll see where we end up."
On a relatively inconclusive day, with teams diverging on planned run programmes, Mercedes' George Russell and championship leader Kimi Antonelli were seventh and eighth in their heavily updated cars.
"I think at the moment that Verstappen is looking the quickest in a single lap and McLaren are looking quickest on the long runs," said Russell.
He added that it was difficult to judge the success of Mercedes upgrades to the floor, sidepods and rear suspension.
"When you bring an upgrade to any circuit, it’s difficult to know what your pure performance is and what it isn't," he said.
"If we had our new car last week, we would have said things were absolutely incredible, but if we had our old version today, I don’t think it would have been much different."