With only the briefest of dry-running windows on Thursday afternoon in what is normally the most revealing of the practice sessions, making any sort of call on the likely competitive shape of the weekend is fraught with hazard. But we can probably say that none of the usual frontrunning teams - McLaren, Red Bull, Lotus - seems to be suffering from the heat degradation of the tyres that caused such a jumble of the order in Spain two weeks ago.
That said, Ferrari, Williams and Sauber - the three over-delivering cars of Barcelona - do look the strongest threat.
Jenson Button's fastest time in the dry-running of P3, almost 0.4 seconds clear of the Lotus of second-fastest Romain Grosjean is flattered somewhat by Jenson being the only guy to get in a dry-track time on the supersoft tyre. But Pirelli reckons this tyre should be worth only around 0.25s over the soft, so not all of Button's speed is accounted for by that.
Lewis Hamilton had yet to put a serious low-fuel lap together but you would reckon if the McLaren is indeed as good as suggested by Button, Lewis must start as favourite for pole.
We've seen nothing spectacular yet from Red Bull, but looking at the ease and consistency with which Sebastian Vettel was pounding out laps in the 1m17s in the morning session suggests the squad should be there or thereabouts come qualifying and race.
Alonso wins the award for visibly hardest trying driver on Thursday © LAT
Belying its reputation as a fast-corner car only, the Lotus looked very convincing indeed in the hands of Grosjean. The choice of Kimi Raikkonen to surrender the opening session in exchange for a power-steering system more to his liking may be a difficult thing to recover fully from, Kimi doing just an out-lap before deciding the system - specifically configured for the unique demands of Monaco - was not to his liking.
Like Red Bull, Mercedes appeared to be running more of its sessions on higher fuel than McLaren, Lotus and others but looks as if it may be around two or three tenths adrift of the Red Bull in race pace. The double-DRS effect will find the car less time around here than at conventional tracks too, so it may be another low-key event for the team.
Taking the award for the most visibly hard-trying driver was Fernando Alonso, but actually both Ferraris looked very driveable, a valuable quality around here. The grip and sheer poise of the McLaren or Lotus might not have been there, but it was responding well to the aggressive efforts of both drivers. Felipe Massa appears much closer to the pace of his team-mate than usual.
Sergio Perez - a star of qualifying last year until his crash - was third quickest in the morning for Sauber, and was consistently the quickest of all in the intermediate-tyred part of second practice, the car again conforming to a pattern in which it goes particularly well when generating tyre temperatures is more of an issue than keeping them alive.
Williams's Pastor Maldonado looks similarly strong, hugely confident between the confines of the walls. But the second drivers in both the Sauber and Williams camps look a few tenths adrift and rather more tentative.
Spanish GP winner Maldonado looked quick again in practice © LAT
Race day is not expected to be wet, so the afternoon times may well be irrelevant. Looking at the morning runs for likely race pace it's difficult to place McLaren and Red Bull on account of them doing only shortish runs. The green-track running of the morning may also be misleading - but for what it's worth the Lotus, Ferrari and Williams looked very evenly matched again over comparable distance runs, all better than the Mercedes.
Kamui Kobayashi, on a similar run for Sauber, looked a little off their pace, but if we overlay Perez's apparently greater one-lap speed into a calculated race-stint run, he would be bang on the Ferrari/Williams level.
It's almost impossible to read between the differing conditions and programmes of Thursday, but the suggestion through that little sliver of a window is that this could be a McLaren race - and that the uplift in performances seen from Williams, Ferrari and Sauber in Spain may actually be real and not just a mirage created by the unusual tyre patterns there.
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