Valtteri Bottas finished top of the times for Mercedes as the post-Spanish Grand Prix test got underway.
The Finn would fall just a tenth shy of his pole time from Saturday in Barcelona as he set a 1m15.511s on the C5 Pirelli tyre, that compared to the C3 he used in qualifying.
That would give Bottas a 1.4s advantage over Charles Leclerc in second for Ferrari, who waited until the end of the day to set his best time on the C2 rubber.
While there was a gulf in lap time, in laps Mercedes and Ferrari were identical with 131 tours of the Circuit de Barcelona-Catalunya each on Tuesday.
Daniil Kvyat also comfortably surpassed the century mark and was third fastest overall for Toro Rosso after his own late flyer on the C4 tyre.
As Nico Hulkenberg took fourth for Renault, with the French manufacturer starting important analysis into their disappointing performances this year.
The German finishing just ahead of Pierre Gasly in the Red Bull, as the Frenchman’s day was cut short by a suspected gearbox problem.
McLaren would be the only team to split their running between both drivers with Carlos Sainz’s morning time leaving him sixth.
Teammate Lando Norris caused a brief stoppage by coming to a halt exiting the pits and would only be ninth fastest overall.
Haas development driver Pietro Fittipaldi took seventh using a set of prototype tyres, just ahead of Racing Point’s Nick Yelloly.
Ferrari junior Callum Illot emerged unscathed from a scary crash at Turn 3 in the Alfa Romeo but would limit his running to just 41 laps as a result.
While Nicholas Latifi completed the timed order in the Williams, amid early speculation he could be being lined up to replace Robert Kubica.
Two other drivers were on track taking part in Pirelli development testing, those being Sebastian Vettel and Sergio Perez.
Though their times were not included in the final graphic, it is reported that the Ferrari driver would have been 10th with the Mexican 11th in his Racing Point.
All official lap times can be seen below:
