Bamber took the lead in the championship-leading #2 car with just eight minutes of the six-hour race to go, when Nick Tandy slowed and moved over in another display of team orders from Porsche in favour of its points-leading trio.

Tandy, Neel Jani and Andre Lotterer had the edge on their teammates around the Circuit of the Americas on a day that Toyota kept the German cars honest – at least for the opening half of the race.

Tandy moved over to let Bamber past for the first time with just over one hour to go, only to retake the lead when the #1 car needed less fuel at its final splash-and-dash pitstop.

He extended a narrow to lead to more than 10 seconds before backing off and then trailing the sister car across the line by just two tenths of a second.

Bamber said: "Congratulations to the #1 car – they drove a great race and would have deserved victory. And Toyota kept us on our toes, too."

Toyota led the race after the first round of pitstops after its pair of TS050 Hybrids double stinted their tyres.

The Toyotas remained within striking range through a mid-race safety car, though they ultimately didn't have the pace to challenge Porsche over the final third of the race.

Sebastien Buemi, Kazuki Nakajima and Stephane Sarrazin ended up third, just over 20s behind the winner.

Kamui Kobayashi, Jose Maria Lopez and Mike Conway were a similar margin back in fourth.

First LMP2 win in 2017 for Signatech

Reigning LMP2 champion team Signatech Alpine finally chalked up its first class victory of the season despite a late-race scare.

Nicolas Lapierre, Gustavo Menezes and Andre Negrao dominated the P2 on the way to a 20s victory aboard their Alpine-badged Oreca 07.

They had been nearly a minute up until stopping to change the rear bodywork to rectify faulty brake lights with minutes to go.

Second and third positions were taken by the two Rebellion Orecas.

Nelson Piquet Jr, Mathias Beche and David Heinemeier Hansson took second, while Bruno Senna, Nicolas Prost and Julien Canal were third – just 3s in arrears after losing 20s in the pits.

Ferrari beats Porsche in GTE Pro

James Calado and Alessandro Pier Guidi held on to take GTE Pro honours for the AF Corse Ferrari team despite twice losing a lead of more than half a minute.

They lost their advantage with the safety car only to rebuild it before a late-race rear puncture brought Pier Guidi into the pits.

The Italian rejoined right in front of the second-placed Porsche of Michael Christensen, but Pier Guidi was to pull away to a five-second victory over the 911 RSR the Dane shared with Kevin Estre.

Sam Bird and Davide Rigon complete the class podium in the second Ferrari 488, three seconds clear of the Aston Martin Vantage shared by Marco Sorensen and Nicki Thiim.

Paul Dalla Lana, Mathias Lauda and Pedro Lamy came back from an early delay to notch up their second GTE Am win of the season for Aston Martin.

Dalla Lana needed a short trip into the garage to repair rear-end damage after he was hit by Francesco Castellacci's Spirit of Race Ferrari and spun, but still took class honours by 50 seconds from the Clearwater Racing Ferrari.

Race results:

Pos.	#	Drivers	Car	Class	Time/Gap
1	2	Timo Bernhard Brendon Hartley Earl Bamber	Porsche 919 Hybrid	LMP1	192 laps
2	1	Andre Lotterer Neel Jani Nick Tandy	Porsche 919 Hybrid	LMP1	0.276
3	8	Stéphane Sarrazin Kazuki Nakajima Sébastien Buemi	Toyota TS050 Hybrid	LMP1	21.956
4	7	Kamui Kobayashi Mike Conway Jose Maria Lopez	Toyota TS050 Hybrid	LMP1	35.026
5	36	Nicolas Lapierre Andre Negrao Gustavo Menezes	Alpine A470	LMP2	15 laps
6	13	Nelson Piquet Jr. David Heinemeier Hansson Mathias Beche	Oreca 07	LMP2	16 laps
7	31	Bruno Senna Julien Canal Nicolas Prost	Oreca 07	LMP2	3.775
8	38	Oliver Jarvis Ho-Pin Tung Thomas Laurent	Oreca 07	LMP2	5.760
9	37	David Cheng Tristan Gommendy Alex Brundle	Oreca 07	LMP2	17 laps
10	24	Jean-Eric Vergne Ben Hanley Matt Rao	Oreca 07	LMP2	25.144
11	28	François Perrodo Emmanuel Collard Matthieu Vaxiviere	Oreca 07	LMP2	18 laps
12	26	Roman Rusinov Pierre Thiriet Alex Lynn	Oreca 07	LMP2	24 laps
13	51	James Calado Alessandro Pier Guidi	Ferrari 488 GTE	LMGTE PRO	25 laps
14	92	Michael Christensen Kevin Estre	Porsche 911 RSR	LMGTE PRO	5.663
15	71	Sam Bird Davide Rigon	Ferrari 488 GTE	LMGTE PRO	31.194
16	95	Marco Sorensen Nicki Thiim	Aston Martin Vantage	LMGTE PRO	34.878
17	97	Darren Turner Jonathan Adam Daniel Serra	Aston Martin Vantage	LMGTE PRO	1'50.831
18	91	Richard Lietz Frédéric Makowiecki	Porsche 911 RSR	LMGTE PRO	26 laps
19	67	Harry Tincknell Andy Priaulx	Ford GT	LMGTE PRO	1'11.110
20	66	Stefan Mücke Olivier Pla	Ford GT	LMGTE PRO	1'40.235
21	98	Pedro Lamy Paul Dalla Lana Mathias Lauda	Aston Martin Vantage V8	LMGTE AM	30 laps
22	61	Matt Griffin Mok Weng Sun Keita Sawa	Ferrari 488 GTE	LMGTE AM	50.059
23	54	Francesco Castellacci Miguel Molina Thomas Flohr	Ferrari 488 GTE	LMGTE AM	33 laps
24	77	Christian Ried Matteo Cairoli Marvin Dienst	Porsche 911 RSR (991)	LMGTE AM	45 laps
25	86	Michael Wainwright Ben Barker Nick Foster	Porsche 911 RSR (991)	LMGTE AM	100 laps
26	25	Vitaly Petrov Simon Trummer Roberto Gonzalez	Oreca 07	LMP2	141 laps