Energy management will be a key facet of the new season, and the teams and drivers are beginning their explorations of the best way to manage the hybrid engines and their electrical components for optimum lap time.
That said, the four teams expected to be closest to the front were in the top positions, with pre-season favourite George Russell of Mercedes third fastest ahead of Ferrari’s Lewis Hamilton.
Williams, who are having their first serious run with their car after delays forced them to miss the week-long ‘shakedown’ in Spain last month, were seventh fastest with Carlos Sainz.
The Spaniard was behind the Haas of Esteban Ocon and 18-year-old British rookie Arvid Lindblad for Racing Bulls.
The Aston Martin team, the centre of a great deal of interest with their first Adrian Newey-designed car at the start of their engine partnership with Honda were towards the back – Lance Stroll, who is driving all day on Wednesday, was more than four seconds off the pace.
Each team ran one driver in the morning session with the others drivers, including world champion Lando Norris and Ferrari’s Charles Leclerc, taking over in the afternoon session from 12:00 GMT.