Toyota opened the World Endurance Championship season by setting the quickest time during the first practice session at an overcast Silverstone circuit.
Sébastien Buemi led the way with a time of 1:40.104s behind the wheel of the #8 Toyota TS050 Hybrid, shared with Anthony Davidson and Kazuki Nakajima.
Buemi's effort was 0.781 seconds quicker than the Porsche 919 Hybrid of Brendon Hartley, which finished second in the LMP1 order.
Despite running with a compromised low-downforce setup against the conventional high-downforce aero package of Toyota, the #1 Porsche of Hartley, Earl Bamber and Timo Bernhard managed to split the Japanese manufacturer's two cars. Mike Conway brought the second Toyota through on a 1:40.960, with Nick Tandy rounding out the quartet of hybrid LMP1 runners.
WEC 6 Hours of Silverstone FP1 result
In the all-ORECA LMP2 category, Rebellion Racing pipped TDS Racing to the fastest time courtesy of a 1:45.913s effort by Mathias Beche.
The Swiss driver edged out Matthieu Vaxiviere in the #28 TDS ORECA by 0.225 seconds, with Alex Brundle slotting slotting the best of the two Jackie Chan DC Racing ORECAs into third.
Completing the top five in class were Roman Rusinov (G-Drive Racing) and Gustavo Menezes (Signatech Alpine).
Aston Martin Racing led Ford and Porsche in the GTE-Pro manufacturer battle as Ferrari struggled to match the pace of its counterparts.
Richie Stanaway set the quickest time of the opening session – a 1:59.110 – in the championship-defending AMR Vantage shared with Nicki Thiim and Marco Sørensen.
The two Ford GTs followed up the New Zealander's benchmark with similar times: Billy Johnson rested 0.382 seconds off the pace with Andy Priaulx a further 0.008 seconds shy, with Frederic Makowiecki lapping fourth for Porsche.
Ferrari, by contrast, ended up rock bottom in the category with its quickest car – the #51 488 GTE driven by Alessandro Pier Guidi – only managing a time of 2:00.081s.
The prancing horse also propped up the order in GTE-Am as Pedro Lamy's Aston Martin Vantage led the category and infiltrated the Pro-class standings.
A second 90-minute free practice session is bookmarked for 16:45 later today (UK time).