Pierre Gasly set the fastest time on the opening day of 2022's final pre-season test in Bahrain, but it was Ferrari who caught the eye with their pace and Mercedes with their radical new car design.
The crucial three-day test, two weeks after an opening shakedown in Barcelona, represents the final chance for drivers to try out their all-new cars before the season begins in just over a week, and there were certainly plenty of signs that teams were upping the ante on Thursday.
While it is still too early to speculate on a pecking order, it is Ferrari who have got the paddock talking with their speed and consistency and Charles Leclerc led from the first hour of Thursday up until the final hour.
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He was only knocked off top spot late on by Pierre Gasly in the AlphaTauri as the Frenchman showed encouraging pace, albeit on the softest tyre.
Gasly's 1:33.902 was six-tenths faster than Leclerc, and 0.4s quicker than Carlos Sainz, who took over from his team-mate in the Ferrari in the afternoon session and seemingly confirmed the Italian giant's speed.
"There's no doubt about it, that Ferrari is looking very handy," said Sky F1's Martin Brundle.
But the potential return of Ferrari to F1 contention was arguably not the biggest story on Day 1 at Sakhir, for Mercedes generated plenty of headlines with a new-look W13 and specifically a radical sidepod design.
As predicted, Mercedes brought a significant car upgrade to the final test but nobody could have foreseen the world champions debuting a car that barely had any sidepods at all, instead using fins and a smaller slot to generate cooling.
The design had rival teams purring and, perhaps unsurprisingly, also led to questions about legality, which a confident Mercedes have knocked back.
Mercedes, however, still had a quiet day when it came to quick times, with George Russell and Lewis Hamilton only placing ninth and 11th and two seconds off Gasly's fastest lap.
They were sandwiched by Sergio Perez in the Red Bull who were also conspicuous by their absence at the front. Perez completed more laps than anyone on Thursday - 138 - though finished the day in the gravel after a clumsy spin, which led to a red flag and an early finish to proceedings.
Are Ferrari the 'strongest' to start F1 2022?
Gasly's fastest time means all four days of pre-season testing so far have been topped by different teams - Ferrari, McLaren, Mercedes and AlphaTauri. But while it is wise to be hesitant about installing favourites at this point in the season, there is little doubt over which team has caught the eye.
"At the moment Ferrari look the strongest," said Mercedes' Russell. "In every low fuel run, consecutive laps, they look very, very solid."
F1 world champion Max Verstappen, who sat out Thursday, added: "They look strong. Very solid, just very decent.
"They're quick, you can clearly see that in the long run and short run and I think that's also good for Formula 1. We all know where they were coming from the last few years so I hope we can match them, be close to them."
Ferrari have understandably been reluctant to accept any sort of favourites' tag or even one that would put them in the mix once the season starts on March 20 in Bahrain, although the signs are certainly promising.
As they were on Thursday for AlphaTauri through Gasly, along with Aston Martin and Williams. Alfa Romeo also enjoyed a much better day, relatively quick and reliable with Guanyu Zhou and Valtteri Bottas racking up the laps.
Haas, meanwhile, missed the morning session due to travel disruption, but Pietro Fittipaldi got out on track in the afternoon. Fittipaldi is the team's reserve driver filling in for the sacked Nikita Mazepin, although Kevin Magnussen will replace the Russian full-time for the American outfit.
Mercedes wow with new sidepod-less car design
Mercedes, meanwhile, caught the attention of the pit-lane with a radically-different W13 car compared to Barcelona, which Hamilton drove out of the garage in the morning. The design has seen Mercedes virtually get rid of their sidepods - which are used to cool the engine - completely, with a bold approach to cooling and generating downforce.
The new look was lauded up and down the paddock, although Red Bull did not appear to be happy. German publication Auto Motor und Sport reported that team boss Christian Horner told them the design was "against the spirit" of the regulations and that parts of the car were "not legal".
Red Bull first insisted Horner had not spoken to anyone before then changing their statement to the team boss not having made an "official comment" on Mercedes' car.
F1 chief Ross Brawn also admitted he was taken by surprise by the concept, though Mercedes - having passed on designs to the FIA before Bahrain - are confident their car is fully legal.
In terms of immediate pace, however, it just did not happen for the Silver Arrows on Thursday.
"I did fear that Mercedes were going to go out this morning and it was going to be 2014 all over again," said Brundle.
"It's not a plug and play car that looks like it's right at the front of the timing sheets come what may.
"They've been struggling a little bit to slow it down, so work to do there. I thought with all that new body work on it, from what I was hearing, it might have turned up and spoiled a lot of people's days."
Mercedes admitted after the session: "We've got quite a lot of work still to do regarding validation of the update kit and will continue the data collection programme over the next few days so it's a bit early to say whether everything is working as expected."
There is still plenty of time for quick times, though, with two days and 16 hours of Bahrain running left. Watch it all on Sky Sports F1, with the action resuming at 7am on Friday.