Heavy rain affected the first half of the Six Hours of Shanghai as safety car periods and two red flags curtailed on-track activity.
Less than 10 green flag laps were held in the opening three hours as drivers struggled to maintain grip in appalling weather.
After a safety car start followed by a red flag that consumed hour one, an initial run of four laps was held but this was cut short by another red flag as the rain persisted.
Another attempt at green flag running in hour three was delayed by a heavy crash for the No. 86 Gulf Racing Porsche 911 RSR on the pit straight, although the return to racing conditions was short-lived as the safety car was scrambled again after Andy Priaulx’s Ford GT spun into the gravel.
Stephane Sarrazin, driving the No. 17 SMP Racing BR Engineering BR1 AER, and Renger van der Zande in the DragonSpeed BR1 Gibson, were the only LMP1 drivers not to pit before the halfway mark.
Everyone else opted to come in, with the No. 1 Rebellion Racing R13 Gibson cycling to the front of the pitting group ahead of Fernando Alonso in the No. 8 Toyota TS050 Hybrid.
Toyota’s pole-sitting No. 7 car lost time in the pits when Jose Maria Lopez was forced to go around the No. 8’s pit box before being pushed back.
The Toyotas, which started first and second, swapped places during the first brief segment of green flag running when Lopez went wide at the turn 14 hairpin, allowing Sebastien Buemi through.
In LMP2, DragonSpeed’s Oreca 07 Gibson led at halfway after Anthony Davidson overtook both Jackie Chan DC Racing Orecas.
GTE-Pro was led at three hours by Kevin Estre, who muscled the No. 92 Porsche 911 RSR into first past the No. 66 Ford GT of Olivier Pla.
After overtaking BMW driver Martin Tomczyk, Estre set about challenging Pla but clipped the Ford into a spin on his way through.
Maxime Martin assumed second in the best of the Aston Martin Vantage GTEs as the opening three hours fell.
In GTE-Am, Team Project 1 cycled to the front of the class following the first round of pit stops.