Valtteri Bottas topped the timesheets this morning, in a session which saw the Finn, Max Verstappen and Lewis Hamilton covered by just 0.123s.

It's unclear if Verstappen could have gone quicker, for the Dutchman was among the last to try the soft tyres due to a red flag period following a spin by Robert Kubica.

Lando Norris was fourth quickest, ahead of the two Ferrari drivers, who, interestingly, posted their best times on the mediums.

Ahead of this afternoon's session, the air temperature is 21.1 degrees C, while the track temperature is 41.2X degrees. It remains bright and sunny.

Having handed their cars over to their teams reserve drivers earlier, George Russell and Kimi Raikkonen will be back in action this afternoon, getting their first taste of the re-profiled Turn 10.

A number of drivers, including Verstappen and Vettel, incurred front wing damage on the new kerb at Turn 7 earlier, while a number had their lap times deleted after exceeding the track limits, mainly at Turn 2.

The lights go green and Raikkonen is first out, followed by Schumacher, Ocon and Giovinazzi.

In no time at all there are 17 drivers on track, all on mediums, Latifi, Alonso and Verstappen the three who opt to sit tight for the time being.

An early moment for Schumacher, who does well to keep it all together as the rear snaps out in Turn 2.

Bottas gets proceedings underway with a 19.087.

Leclerc goes second, ahead of Norris, Con, Sainz and Tsunoda.

Quickest in S1, Hamilton loses a little pace in the second sector, finally crossing the line at 19.323 after losing time in S3 behind Tsunoda.

No sooner has Alonso gone third with a 19.751, than Verstappen goes top with a 19.041.

Meanwhile, the wind is clearly picking up, with a headwind into Turn 1.

Stroll's time is wrecked when he comes up behind a very slow Mazepin who has opted to abort his lap.

As Vettel reports that he is struggling with the year, there are no such problems for Bottas who goes quickest in all three sectors, finally crossing the line at 18.419.

Sainz sheds a piece of bodywork after going over the kerbs at Turn 9. The VSC is deployed while the piece of carbonfibre is removed.

Hamilton goes second with an 18.461. Verstappen responds by going quickest over in the final sector but remains third, 0.366s off Bottas' pace.

When Mazepin declares "box, box", he is asked if he is OK. "Amazing," comes the reply.

Meanwhile, Tsunoda complains that his car "switched off".

With 40 minutes remaining, the Mercedes pair are among the first to bolt on the softs. Norris, Vettel and Schumacher follow suit.

Bottas consolidates his top sport with an 18.309, while Hamilton responds with an 18.170.

Vettel goes fourth with an 18.947, the German seeming to benefit from the upgrade package that was only available to teammate Stroll last weekend.

Gasly goes third (18.728) while Norris can only manage a 19.092 to go sixth.

An 18.335 sees Leclerc go third, with Sainz going fifth (18.674) moments later.

Verstappen heads out on the softs as Alonso goes fifth with an 18.518, slotting in behind his Alpine teammate.

Verstappen posts a PB in S1, as Giovinazzi goes eleventh overall with a 19.122.

Following another PB in S2, Verstappen runs wide in Turn 10 and subsequently aborts the lap.

Fun and games in the pitlane, as Mazepin is released into the path of Raikkonen. The wily old Finn continues unruffled and maintains track position.

Perez can only manage tenth (18.918), just one spot behind his Red Bull teammate.

"Box, the tyres are good for one lap," insists Mazepin.

With twenty minutes remaining, attention now shifts to Sunday afternoon as the long runs get underway.

All bar Perez are on track, and with the Bulls down in 9th and 10th the big question is, is the Austrian team struggling or merely sand-bagging. Our money is on the latter.

Told he is faster than Lance, Vettel is told to mind his temperatures.

Verstappen goes cross-country in Turn 8, having been told to mind his front-left in terms of temperature.

Alonso complains of a lack of rear grip as Gasly is warned that the wind is picking up.

"You're right on the money," Perez is told, the Mexican seemingly on the same pace as the Mercedes which has stabilised at 23.3.

With 3:40 remaining, the top 16 are covered by just 1.043 seconds.

Long run pace has the Mercedes pair out front, with Alonso lapping quicker than Verstappen.

Red Bull sends its drivers out for a late final lap, however it almost ends in disaster when they are released into the paths of Leclerc and Raikkonen.

The session ends, and as it does the TV cameras pick up on damage to the endplate on the right side of Verstappen's front wing.

Hamilton is quickest, ahead of Bottas, Leclerc, Ocon, Alonso, Gasly, Tsunoda, Sainz, Verstappen and Perez.

Vettel is eleventh, ahead of Norris, Giovinazzi, Stroll, Ricciardo, Raikkonen, Russell, Latifi, Schumacher and Mazepin.

So, Mercedes is quickest, and while Red Bull's lack of pace suggests the team could be sandbagging, there is no arguing with the fact that Verstappen is continuing to make mistakes.

Furthermore, while Alpine and Alpha Tauri are looking good, McLaren isn't.

That aside, with just 0.043s covering the top 16, we should be in for some fun tomorrow.

Check out our Friday gallery from Barcelona, here.