Hot off the heels of a Monaco Formula 1 weekend where it was distinctly fourth-best, McLaren has showed up again at the Barcelona Grand Prix - leading the way in FP2 through Lando Norris.

But is it the return to form that the headline times suggest?

McLaren's new front wing - which it's elected to leave off the car at the previous two races - does appear to be working much better at Barcelona, as does the MCL40 in general. Norris acknowledged as much, though did admit McLaren had "a lot of problems" including vibrations in FP2 (his only session of the day, having handed his car over to Leonardo Fornaroli for FP1).

"It's such a different layout to the last few weeks, you can't even compare it...I feel like the fastest corner over the last few weeks is like the slowest corner here," he said.

"It's all much more open, wide, arced corners instead of tight and twisty. Clearly it suits the car a lot better, so I'm just happy that we seem to be in a more familiar place to Miami in terms of pace.

"I don't think you're going to ask anyone and say, 'Yeah the car felt mint today', because I think it's hot, it's weird with the rubber, it's weird how the car kind of grips and ungrips at times and with the wind it can really affect it too.

"So it's certainly not easy out there, but the fact that the car still seems to be able to put in good laptimes, even without feeling amazing, it's a good sign. Still means there's stuff we want to improve for tomorrow, and that's still a good sign considering the pace we had."

But McLaren might need to bank on that improvement, as it appears to be behind all of its rivals on long-run pace - with the usual caveat about fuel loads.

'Big four' FP2 long-run pace

1 George Russell (Mercedes) 1m21.195s (soft, four laps)
2 Kimi Antonelli (Mercedes) 1m21.425s (soft, seven laps)
3 Charles Leclerc (Ferrari) 1m21.696s (medium, seven laps)
4 Max Verstappen (Red Bull) 1m21.818s (soft, nine laps)
5 Lando Norris (McLaren) 1m22.029s (soft, eight laps)
6 Oscar Piastri (McLaren) 1m22.336s (medium, six laps)
7 Lewis Hamilton (Ferrari) 1m22.594s (medium, six laps)
8 Isack Hadjar (Red Bull) 1m22.929s (soft, three laps)

Degradation was noted on all compounds and most runs do point to a significant drop-off, so take into account the length of Russell's run (four laps) versus Leclerc's (seven) and the difference in compound and Mercedes' advantage might not be quite as decisive as a half-second margin would suggest.

Russell's medium-tyre run was a nine-lap one that averaged out at a 1m21.788s, though scrub off two outlier laps at the end and that becomes a 1m21.369s, which seems to be encouraging Mercedes. The same goes for the upgraded Ferrari; take out one Leclerc lap that was three quarters of a second shy of his next-worst and that average comes down to a 1m21.495s.

But go back to Norris's comment - that "it's weird with the rubber" - and therein lies not just the likely answer as to why McLaren might still be in the picture, but also potentially the key to the outcome on Sunday - which might come down to who can keep the tyres alive the longest.

Hamilton - well down in the single-lap and long-run charts - said Friday's running offered probably the lowest grip he's ever experienced at Barcelona during a race weekend and that the tyres "only last one lap".

"This is going to be a real true test of how cars can keep the tyres alive across race stints and it is a place where race pace always dominates," said Mercedes deputy team principal Bradley Lord.

"So one lap is obviously of interest, and interesting for qualifying to see where we'll end up, but what really is important is making sure we can hang on to the tyres over a race stint. And the long runs look close but competitive, particularly for George on the medium tyre."

Tyre supplier Pirelli has gone a step softer than usual for Barcelona with its compound choices, with the C2 the hard, the C3 the medium and C4 the soft. That's been done with two aims: to encourage more pitstops and to make the hard tyre an option in strategies.

Only one of the frontrunners attempted a race run on the hards, with Verstappen averaging a 1m21.911s that stands up reasonably well.

The Red Bull appeared to be in no-man's land on single-lap pace - Verstappen was nearly nine tenths off Norris - but was closer on long runs, though chief engineer Paul Monaghan said matter-of-factly of Red Bull's day that "we may not be on for an A star".

"We lack a bit of balance, we lack a bit of grip," said Monaghan.

"None of it should come as a surprise. I suspect our opposition are actually very similar. We all are going to encounter similar problems around here.

"It's a tough, demanding circuit, and it's really hot. What laptime do we manage whilst incurring those problems is, I think, likely to be the biggest issue we face."