Toyota driver Sebastien Buemi passed both Ferrari 499Ps before a safety car period and went on to lead the opening hour of the 100th-anniversary edition 24 Hours of Le Mans.
The Swiss driver overtook James Calado and pole-sitter Nicklas Nielsen on the opening lap, as Mike Conway moved up to third in the other Toyota GR010 Hybrid.
The safety car was then brought out following an accident for the Action Express Racing Cadillac V-Series.R of Jack Aitken at the exit of the Daytona Chicane and a spin into the gravel for LMP2 driver Mark Kvamme.
It took over half an hour for the new safety car procedure to shake out, which involves a wave-by procedure followed by a merging of three safety cars into one, and finally a filtering of the field into class order.
The safety car benefited Hertz Team JOTA, which started from the back of the grid after failing to set a lap time in qualifying but was able to latch onto the tail of the Hypercar class courtesy of the ‘drop back’ procedure that is new to the regulations this year.
When racing resumed, Conway overtook Nielsen for second down the inside at the kink before Indianapolis and it looked as though the Toyotas might settle into a controlled one-two.
However, as the Toyota drivers started to manage their soft Michelin tires, the medium-shod Ferraris bounced back and Conway was passed by Nielsen at Mulsanne corner.
Nielsen then pitted shortly before the end of the hour, which promoted Calado to second after the No. 51 Ferrari driver dispatched his fellow Englishman Conway at the Daytona Chicane.
Felipe Nasr tailed the leading quartet of LMH cars in his LMDh-spec No. 75 Porsche 963.
Laurens Vanthoor had a notably strong start in the No. 6 Penske-run Porsche, climbing from ninth to net sixth and overtaking his teammate Michael Christensen on the way.
In the all-Oreca 07 Gibson LMP2 class, Paul-Loup Chatin led the opening hour for IDEC Sport ahead of Team WRT’s Robert Kubica and JOTA’s Pietro Fittipaldi.
The No. 63 Prema Oreca driven by Daniil Kvyat incurred an early setback when it made a lengthy unscheduled pit stop after picking up debris from Aitken’s accident.
Corvette Racing was one of several GTE-Am teams to pit under the safety car, causing Nicky Catsburg to drop from the lead behind the competitors that stayed out.
Davide Rigon led after one hour in the No. 54 AF Corse Ferrari 488 GTE Evo, with the Porsche 911 RSR-19s from Team Project 1 and Iron Lynx running close behind.