Daniel Ricciardo gets his first proper taste of the new Formula 1 regulations when he takes his McLaren out on track tonight in Barcelona.
After watching his teammate Lando Norris complete 472 kilometres on the first day of pre-season testing on Wednesday, the Australian gets his chance today, starting at 7pm AEDT.
F1 started the first of its two, three-day testings on Wednesday, with many big names hitting the Barcelona circuit.
Reigning world champion Max Verstappen was out all day in his Red Bull, while Mercedes gave both Lewis Hamilton and George Russell a chance on day one.
Ricciardo will head out on track with a car that appeared sharp in the first testing session of the year.
Norris set the fastest time of the day, with a lap of 1 minute 19.586 seconds, with both Ferrari drivers of Charles Leclerc and Carlos Sainz coming second and third.
While this is promising, McLaren's executive director James Key was quick to hose down any suggestion that the historic team had the fastest car.
"We're not taking any notice of lap times at the moment, it's all about learning and following our own directions and priorities," Key said at the end of day one.
"We gathered some important data points during this first day of testing and learned a great deal, both to carry forward for the rest of this test and also to use as we develop the car further.
"I think we can be pleased with the number of laps we've covered with Lando today and look forward to going again with Daniel tomorrow."
World champion Verstappen goes the distance on day one
No man drove more kilometres on day one than reigning world champion Verstappen, who logged 147 laps around the Circuit de Barcelona-Catalunya.
This was 20 laps more than his nearest competitor, Fernando Alonso, and more than both Mercedes drivers combined.
Verstappen's near 700km day showed promising signs that Red Bull has produced a car with good reliability, something which will be a key factor heading into the 23-race F1 season.
The Dutchman said his Red Bull felt quick in Barcelona, in what could be an early sign of confidence from the new champion.
"I think the car looks good but the most important thing is that it is fast, and that's what we are trying to see," he said.
"We needed the mileage to see how the parts held up. Everything worked pretty well, so it was a good start and a positive day."
Tough day for Alfa Romeo and Haas as troubles hamper track time
While those who were are the front of the grid last year drove well in excess of 100 laps each on Wednesday, the same could not be said for last year's two backmarkers.
Haas and Alfa Romeo were the only teams not to record 100 laps, with both teams unable to register 50.
Alfa Romeo was compromised with issues all day, which was a less-than-ideal start for new driver Valterri Bottas.
Bottas — who finished third in last year's drivers' standings with Mercedes — said "costly" time was wasted in the garage but he believed his team would be able to resolve their problems in time for the second day of testing.
"I just now hope we can get a good two days running here in Barcelona," he told F1 media.
"Yes, we did have a few issues, and the issues we had were pretty costly with time.
"Some issues we had with reliability, some with mechanical things."
In the Haas garage, floor damage stunted much of Mick Schumacher's afternoon in Spain.
The German was quicker than his teammate, Nikita Mazepin, who went out in the morning.
Both appeared to be off the pace, but team boss Guenther Steiner said, like Alfa Romeo, he was hopeful their issues would be quickly resolved.
"It's been one of those days where a few small issues end up costing you considerable time in the garage," he said.
"All being well tomorrow, we'll have greater reliability and we can get into a more thorough run-plan for both Mick and Nikita."
