Romain Grosjean offered himself and Haas some consolation following his troubled Spanish Grand Prix last Sunday by topping the timesheet half-way through the first day of testing in Barcelona.
The Frenchman clocked in with the best time and a lap in 1m18.449s that was 0.094s clear of Mercedes' Lewis Hamilton and 0.758s better that Red Bull's Max Verstappen.
The Dutchman edged out Renault's Carlos Sainz, while McLaren's Stoffel Vandoorne was fifth.
Canadian rookie Nicholas Latifi put 61 laps and the sixth best time on the board for Force India, finishing the half session ahead of Ferrari's Sebastian Vettel who posted his time on Pirelli's soft tyres.
Oliver Rowland made his F1 debut with Williams, while Lando Norris worked through Pirelli's 2019 tyre programme in a second McLaren, with George Russell also running for the benefit of the tyre supplier with Force India.
Antonio Giovinazzi for Sauber, Russell and Sean Gelael for Toro Rosso closed out the bottom list of drivers.
Gallery: The beautiful wives and girlfriends of F1 drivers
Keep up to date with all the F1 news via Facebook and Twitter