Lando Norris and Oscar Piastri head to potentially the biggest challenge of their Formula 1 title showdown in Las Vegas, and it's far from certain that the responses McLaren has made to its 2024 struggles at this track will help it avoid a repeat.
A combination of tyre struggles - which all teams faced - to varying degrees in the cool of the night desert, plus aerodynamic compromises triggered by the long straights, left both Norris and Piastri on the back foot.
Difficulties with graining and a general lack of grip last year resulted in Norris managing no better than sixth, one place ahead of Piastri, on a weekend where rival Max Verstappen sealed his fourth world title while George Russell won the race for Mercedes.
While McLaren was not alone in being challenged by the unique characteristics of Las Vegas, it risks suffering a lot more than rivals there because the need to get tyres into the right temperature window is counter to the strength its package has shown in keeping its rubber cool.
There has been a trend this year for Verstappen in particular to be able to hold an advantage over McLaren on cool days when thermal degradation is not a problem.
McLaren team boss Andrea Stella said his team's woes last year were on multiple fronts and were not just about not getting the tyres up to temperature in qualifying and then graining heavily in the race.
"We had also some aerodynamic issues when we tried to offload the rear wing," he said.
"We saw that we were losing too much efficiency, and we also had some issues with the set-up of the car trying to compensate for this graining and some of the understeer."
McLaren's post-race analysis gave it some direction in what to do differently this year, but it knows that if others have made more progress, then it will not show an uptick in positions.
"We know in which direction we should change compared to last year, but will it be enough to be competitive now? We will only see it in Vegas," Stella cautioned.
"But definitely we took actions in response to what we saw last year because certainly the performance wasn't satisfactory enough."
The uncertainty about how things will shake out this year is increased because of improved tyres that Pirelli introduced this season.
The stronger construction has reduced graining at other tracks in 2025, so in theory teams such as McLaren that suffered in Las Vegas 12 months ago may not experience such a nightmare this time out.
But with early forecasts suggesting temperatures could be cooler than last year - increasing the risk of tyres sliding on the cold surface - graining will remain on the table.
The answer about how much of a problem it will be won't come until the race weekend, and may even have to wait until second free practice when conditions mirror what it will be like in the race.
Ferrari enjoyed quite a competitive showing last year, with Carlos Sainz starting on the front row and finishing third, ahead of then team-mate Charles Leclerc.
Team principal Fred Vasseur was well aware that the quirks of the tyres last year played their part in Ferrari's strong performance, and accepted that things may be different this time around.
"Last year the race was clear, it was quite extreme on tyres," he said. "It was a lot about putting the tyres in [the right] temperature. Perhaps now with the new [tyre] it will be a bit different."
What will be most interesting to see is whether Mercedes, which was in a class of its own in Las Vegas last year, can repeat its form this time out.
The team's 2024 car trait of overheating its rear tyres, which hurt it at other tracks, proved to be the thing to have in Las Vegas as it helped its drivers get their rubber into the right operating window.
What the team does not know right now is if the improvements it has made in controlling those rear temperatures for this season will wipe out what made it so strong 12 months ago.
Russell said: "I expect us to be strong. I'll be very surprised if we're as strong as we were last year, but we hope so."
Mercedes boss Toto Wolff - who joked that Mercedes would perhaps be best placed by running its 2024 car - doubted his squad could repeat what happened in 2024 as Russell led home team-mate Lewis Hamilton.
"I've said let's just keep exactly the same car that we had last year, let's not change it, but unfortunately that's not the case anymore," he said.
"So we've got to be very analytical of what is the car that we need for Las Vegas? What is the ambient [temperature]? And can we replicate the kind of performances?
"I doubt that. We just need to go there open-minded."
