Max Verstappen set the pace in a first practice session that gave little insight into the true competitive picture at the Spanish Grand Prix.
The world champion was a massive 0.768 seconds quicker than team-mate Sergio Perez, who trails the Dutchman by 39 points in the championship.
Alpine’s Esteban Ocon and Pierre Gasly were third and fifth fastest, split by the Alpha Tauri of Nyck de Vries.
Many teams were trying upgrades on a new version of the Barcelona track.
The fiddly chicane in the final sector, which was introduced in 2007, has been replaced and the circuit now has two fast right-handers to complete the lap, as it did in its first iteration from 1991 to 2006.
There had been questions as to whether the last corner would be taken flat-out, but in first practice it was not by anyone.
Many drivers – including the Red Bull pair – were complaining that their cars were “bouncing” going into the final corner.
This marked a return of a aerodynamic problem known as “porpoising” that dominated much of last season and will be something teams will want to try to eradicate for the rest of the weekend.
Aston Martin’s Fernando Alonso, whose car has a series of revisions focused mainly on the front and rear wings, was sixth fastest ahead of Kevin Magnussen’s Haas.
The Ferraris of Charles Leclerc and Carlos Sainz were eighth and ninth ahead of Mercedes driver George Russell.
Ferrari have brought a revised sidepod and floor edge which they hope will address the inconsistency of the car’s handling on long runs that has blighted their season so far.
There are enough parts for both cars but Sainz was running the new design and Leclerc the old as the team sought a comparison of their effects.
