Huge applause as Fernando Alonso heads out onto the circuit. He completes a minor milestone by successfully navigating the first couple of corners.

Sebastian Vettel and Kimi Raikkonen have also gone out for Ferrari. Everyone has hard tyres on at the moment.

Valtteri Bottas is nowhere to be seen in the Mercedes garage. Maybe he has gone to play tennis.

Lewis Hamilton, meanwhile, is getting strapped into his car. He'll be out any minute as final practice gets under way.

Image source, BBC Sport

Here's an explanation from Mercedes about the problem with Valtteri Bottas' car.

A Mercedes spokesperson said: "We had an electrical fault on Valtteri's PU last night. To fix it, we broke the curfew, and it was resolved. However, in putting the engine back together, we have discovered a small water leak. So we have put PU1 back into Valtteri's car (used at the first four races) and we hope that he will be able to run at some point in third practice - the boys are working flat out on it to make that possible. PU2 will have the water leak fixed to be ready as a spare and for future use at the upcoming races."

Jennie Gow
BBC Radio 5 live pit-lane reporter

It was not an ideal night for the Mercedes mechanics and engineers. They found a problem with Valtteri Bottas' engine, an electronic fault. It means Bottas will have limited, if any, running in final practice.

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Lewis Hamilton's Friday may have been pretty much perfect but it's a busy start to the morning on the other side of the Mercedes garage.

Valtteri Bottas' car has an electrical problem and the team has broken curfew to try and fix it. His Mercedes is currently up on the stands with most of the bodywork off.

Andrew Benson
Chief F1 writer in Barcelona

Lewis Hamilton did a Twitter chat with his followers on Friday evening, and in amongst the questions about music and general fan-dom was the revelation that the Mercedes had felt “amazing” on Friday. “It’s definitely a step forward,” he told TV crews after Friday practice. “Everyone worked very hard to bring the upgrade here, as every team did. They’ve done a great job with the package to move forward in this fight and make us stronger. We’ve all stepped forward.”

However, Hamilton played down the difference he expected it to make to Mercerdes’ competitive position. “It’s not really changed anything,” he said. “The gap looks like it’s within a 10th between us and Ferrari, which is the same as the last race; we’ve both made pretty much the identical step.”

Fancy a potted history of the Spanish Grand Prix as told by Jack Nicholls and Tom Clarkson? Then you are in luck because we happen to have one right here. Watch it below.

Robert McPhee: The man running HasMcLarenBrokenDownToday shut it down as it requires too much effort to update every day on a race weekend.

McLaren's latest breakdown reminded me to check in on the website hasmclarenbrokendown.com, external but sadly it seems the website itself has broken down as well...

Image source, ..

All the attention was on Fernando Alonso in the paddock last night.

Is there a danger that the Spaniard will be remembered more for deck chair-based memes and bad luck than winning two world titles? He is not worried about his own reputation, but has warned Honda they are risking theirs.

"It is not my career, my ability, my image [at stake]. It is their career, ability, money and image," he said.

"I try to support the team and drive as fast as I can, but the problem is not entirely mine. It is much bigger for them."

Andrew Benson
Chief F1 writer in Barcelona

Image source, Getty Images

Mercedes turned up at the Spanish Grand Prix with a major car upgrade, with a raft of dramatic-looking new parts, and so far they seem to have done the job. 

Mercedes struggled at the last race in Russia, even though Valtteri Bottas won it, but they have started this weekend looking very strong. Lewis Hamilton and Bottas were one-two in both practice sessions on Friday and their race pace was a long way ahead of Ferrari’s. 

Ferrari team boss Maurizio Arrivabene played it down, reminding everyone that the same had been the case at the first race of the season in Australia. Have Mercedes made a decisive step forward? Let’s find out.

Image source, Getty Images

While there was little to smile about for Fernando Alonso, Friday practice for the Spanish Grand Prix had Lewis Hamilton positively beaming. 

Just when Ferrari had seemingly got the measure of them, a raft of upgrades brought to Barcelona appears to have given Mercedes the edge again as Hamilton finished fastest yesterday.

So are they back out in front? Today's final practice and qualifying should give us a clearer indication.

Is it a comedy?

A tragedy?

A horror story?

Whatever genre Fernando Alonso's season fits into another chapter was written yesterday.

After managing to negotiate three corners in first practice, his engine went kaput. Instead of getting some much-needed laps in he went off to play tennis.

So will today go without a hitch, or will there be more trouble afoot for the Spaniard?

Best bring your football boots just in case, Fernando.

Image source, Getty Images