Lando Norris took another huge step towards the 2025 Formula 1 title with Las Vegas Grand Prix pole - but may need to overcome a major weakness, both his own and McLaren's, to make it stick.
Norris soared in the wet conditions of qualifying, but performance over stints was in any case a bigger concern coming into the weekend - given McLaren was badly graining-limited in the race last year, leaving Norris powerless to prevent an early Max Verstappen coronation on that occasion.
A common consequence of low track temperatures, (front) graining - a tyre wear irregularity that creates sub-optimal rubber patterns and wrecks grip - was clearly weighing heavily on Norris's pre-weekend mind on Wednesday.
Asked about the McLaren being historically tricky to drive and how Vegas multiplies that effect, Norris said that in developing the 2025 car McLaren "certainly opened up that window of workability and driveability" - but that "Vegas again is just a whole different ballgame in terms of cold, low grip".
"I always struggle a lot with front graining," he said, speaking before the track action for the weekend started. "I'm definitely better now - I think I probably used to be the worst on the grid.
"I hate it. I hate understeer. I hate the front not working - those kinds of things. And that's something that can happen a lot here as well and has done in the past.
"If I go out and FP1, FP2 and I grain the fronts, I’m not going to be very happy when I come in. And you're going to ask me in the [media] pen, and I'm going to probably say it's been a crap day."
In the end, Norris wasn't particularly doom and gloom after Thursday practice, reporting "a better feeling in the car than we had last year", yet with the caveat that high-fuel running was so limited by the day's disruptions.
Yet the following day, with pole in the bag and things looking rosy on paper, McLaren has acknowledged the MCL39 isn't necessarily responding how it would like when it comes to graining.
Said team boss Andrea Stella: "We managed to be competitive in wet conditions in Vegas, which are actually quite exceptional. And, if anything, we saw yesterday that we were relatively OK over a single lap with the soft tyres - even though not many cars actually were able to complete a lap in the second session.
"But when it comes to race stints, we will see tomorrow.
"There's definitely graining again here. It almost looks like the improvement on the graining side that we have had [on other tracks] with the 2025 tyres is not realised somehow."
The graining in Vegas is "of a different nature", Stella explained, "and this makes the tyres grain pretty much at the same level as last year".
Potentially an extra complication is the fact that the usual in-weekend build-up of grip through rubber being laid down has been washed away by rain - though Stella said there's graining anyway "pretty much in every condition here", and hoped that higher forecast ambient temperatures on Saturday (race day) will help out.
"In practice here, we have seen that there was graining at the front, obviously, very visibly. But it's not like the rear was in a great situation," he added. "So you will have to see which axle is the most important in terms of protecting it.
"I expected the front to be the one. So like when you have front graining, you need to try and reduce the demand on the front axle - and in particular try to avoid having to steer too much, because in this low-grip condition this may cause some damage to the surface, and then this can instigate the graining.
"This is as technical as I can be. I don't think I know more than that, so I really shared all my knowledge."
It is therefore Norris - and obviously team-mate Oscar Piastri, but Norris has admitted front graining is a particular weakness of his - who will need to be "technical" in how he approaches the first laps on Saturday.
And it is other teams' drivers, if they feel they have an advantage in that respect, who will need to look to force Norris into doing things he doesn't want to do with the steering, to the front tyres.
Based on limited data from Friday, Pirelli has earmarked a one-stop strategy - medium-hard - as the fastest, with a lap 20-26 pitstop window. But medium-hard-hard has been mentioned as a viable, "very close" alternative - and it's one that cars might be forced into due to graining on the medium.
Pirelli F1 chief Mario Isola warned drivers will have to be very careful in the first couple of laps in how they approach getting tyres into the temperature window, as you run a serious risk of "killing the front" very early on.
"I don't have a clear idea if they are planning a one-stop or two-stop," he said of teams' approaches. "With the very little data that is available, they need to be flexible.
"We know that the track is green [the rubber build-up washed away after the rain]. We know that with a green track yesterday they had graining. If at the start of the race they have to push - because obviously they are fighting for position - and they initiate graining, then it's difficult to clean it.
"And in that case a two-stop can be an advantage. If you start to have degradation because of graining that is not manageable, you simply have degradation and probably here a lot of understeer because the graining is more on the front, then you have an advantage to stop twice."
More from qualifying day in Vegas
The key reasons behind Norris topping F1 2025's toughest session
Winners and losers from 2025 Las Vegas GP F1 qualifying
Fresh Piastri F1 title blow and odd Hadjar near-miss explained
Hamilton's latest low in his 'hardest year' in F1
Mercedes avoids penalty, exonerated after 'IT security issue'
Norris has led 130 out of 142 laps at the last two grands prix, making a crucial break from Piastri and Verstappen in the title race. That two-race stretch was as simple as it gets at this high a level - and Vegas doesn't look like it'll be as simple.
But if it turns out he can run the race that he wants to run, despite the looming threat of a problem he feels he was "worst on the grid" at managing, then this is almost certainly his year.
