Lewis Hamilton finished fourth in the opening practice session for Sunday's British Grand Prix.
Hamilton was almost one second down on Red Bull driver Pierre Gasly, the surprise pacesetter in the opening running at Silverstone.
Valtteri Bottas finished second for Mercedes with Max Verstappen third. Ferrari's Charles Leclerc was fifth ahead of team-mate Sebastian Vettel.
Hamilton heads into Sunday's event bidding for a record sixth win in front of his home supporters, with a record crowd of more than 140,000 expected to cheer him on.
Verstappen won the Austrian Grand Prix a fortnight ago, the first non-Mercedes winner of the new campaign.
And Red Bull carried their impressive form over to the 10th round of the campaign with Gasly topping the order for the first time in his career.
The young Frenchman, who has struggled on his promotion from Toro Rosso to the senior team this year, was half-a-second clear of Bottas.
Verstappen was 0.836 sec slower than Bottas as Hamilton finished half-a-second shy of his team-mate.
Romain Grosjean raised eyebrows in the opening minutes when he crashed in the pit lane.
The error-prone Frenchman hit the barriers on the pit exit, ripping off his front wing.
Following repairs, Grosjean then spun later in the session.
The newly-resurfaced track caused problems for a number of drivers, with British rookies' George Russell and Lando Norris, and Ferrari driver Leclerc losing control of their cars. The trio all survived without sustaining damage.
Alfa Romeo driver Kimi Raikkonen spluttered to a standstill midway through the session. The Finn's engine expired on the Wellington Straight and the running was temporarily stalled to recover his stricken machine.
Despite his spin, 19-year-old Norris finished 11th with Russell a lofty 17th for his struggling Williams team.
