Toyota Gazoo Racing consolidated its qualifying 1-2 to lead a dramatic opening hour of the Six Hours of Silverstone.
Kamui Kobayashi consolidated his pole position from Sebastien Buemi as the Toyota TS050 Hybrids set off in close company at the head of the field.
They ended the hour one lap ahead of Neel Jani in the No. 1 Rebellion Racing R13 Gibson after an incident-filled opening for the non-hybrid LMP1 cars.
A congested run through the opening right-left sequence of corners resulted in contact between the No. 17 SMP Racing BR Engineering BR1 AER and the No. 3 Rebellion.
SMP driver Stephane Sarrazin was adjudged to have closed the door on Mathias Beche into the Abbey right-hander and received a drive-through penalty despite both cars spinning from the contact.
The sister Rebellion, driven by Neel Jani, then ran wide and was almost collected by his team-mate.
All three cars fell to the rear of the LMP1 pack but have since worked their way through the order.
Jani was third at the close of the opening hour, 1-minute 41 seconds adrift of Kobayashi, after profiting from a terminal mechanical problem for the No. 11 SMP car of Mikhail Aleshin.
In LMP2, the pole-sitting Jackie Chan DC Racing Oreca 07 Gibson maintained its lead with Weiron Tan leading Giedo van der Garde in the No. 29 Racing Team Nederland Dallara P217 Gibson by half a minute.
The sister Jackie Chan DC Oreca, which started second, was handed a 10-second drive-through penalty for jumping the start and emerged from that in fourth, behind the No. 36 Signatech Alpine A470 Gibson.
The GTE-Pro order shuffled around in the opening corner drama as the No. 67 Chip Ganassi Racing Ford GT dropped away from its pole starting position.
Olivier Pla locked up into turn one before running wide and slipping to the back of the field, while Kevin Estre snuck through into the lead from fifth.
Estre, driving the No. 92 Porsche 911 RSR, went on to build a gap to the battling class pack behind, entering the first round of stops just before the top of the hour with a 10-second lead.
Sam Bird was second in the No. 71 AF Corse Ferrari 488 GTE after overtaking Marco Sorensen’s Aston Martin Vantage GTE.
In GTE-Am, Egidio Perfetti led much the opening stint from pole in the Team Project 1 Porsche 911 RSR.
The Norwegian was overtaken by Salih Yoluc in the No. 90 TF Sport Aston Martin Vantage GTE early on but restored his position soon after before stretching the gap to over 10 seconds by the first stops.