A run on the C5 Pirelli tyres put Robert Kubica at the top of the timesheet on the first morning of the second Formula 1 winter test.

The Alfa Romeo reserve driver would use the softest compound to set a 1m16.942s with 40 minutes to go before lunch to go six-tenths clear of the field.

With this week signalling the last three days of running before Practice 1 in Australia, for some teams it was a continuation of the work began last week while others brought new parts they expect to use in Melbourne.

It was a low-key morning at both Red Bull teams, however, as Alex Albon and Pierre Gasly only completed installation laps in first three hours before emerging almost simultaneously with an hour to go.

During that time the screens were erected in front of their garages, something that only allowed when the floor is off under new regulations for 2020, suggesting possible mechanical issues.

Despite the limited running, however, Gasly was still able to go second fastest with a lap on the C4 tyres with Albon only 0.01s behind in third albeit using the harder C2 compound.

Interestingly, the Red Bull driver was fractionally faster than Lewis Hamilton and Mercedes in fourth on the same tyre.

The world champion though had a much more productive morning with an overall best 88 laps of the Circuit de Barcelona-Catalunya under his belt.

Lance Stroll continued Racing Point's strong pre-season in fifth, with Sebastian Vettel recovering from a spin at Turn 8 to log a productive 84 laps and the sixth-best time on the C3 tyre.

Daniel Ricciardo was seventh for Renault, just 0.007s ahead of Carlos Sainz's McLaren though on one step harder tyres (C2 vs. C3) than the Spaniard.

Nicholas Latifi caused the second of two red flags in the morning in the Williams, the first to clear gravel thrown on the track by Vettel's spin.

An engine issue was later confirmed as the cause of his stoppage.

And finally, Romain Grosjean completed the top 10, with the Frenchman the only driver not handing the car over to his teammate for the afternoon.

Full times and lap counts from Wednesday can be seen below: