Porsche drivers Timo Bernhard, Brendon Hartley and Earl Bamber claimed a fourth straight FIA World Endurance Championship victory in Austin.
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.
|1||2|| Timo Bernhard
|Porsche 919 Hybrid||LMP1||192 laps|
|2||1|| Andre Lotterer
|Porsche 919 Hybrid||LMP1||0.276|
|3||8|| Stéphane Sarrazin
|Toyota TS050 Hybrid||LMP1||21.956|
|4||7|| Kamui Kobayashi
Jose Maria Lopez
|Toyota TS050 Hybrid||LMP1||35.026|
|5||36|| Nicolas Lapierre
|Alpine A470||LMP2||15 laps|
|6||13|| Nelson Piquet Jr.
David Heinemeier Hansson
|Oreca 07||LMP2||16 laps|
|7||31|| Bruno Senna
|8||38|| Oliver Jarvis
|9||37|| David Cheng
|Oreca 07||LMP2||17 laps|
|10||24|| Jean-Eric Vergne
|11||28|| François Perrodo
|Oreca 07||LMP2||18 laps|
|12||26|| Roman Rusinov
|Oreca 07||LMP2||24 laps|
|13||51|| James Calado
Alessandro Pier Guidi
|Ferrari 488 GTE||LMGTE PRO||25 laps|
|14||92|| Michael Christensen
|Porsche 911 RSR||LMGTE PRO||5.663|
|15||71|| Sam Bird
|Ferrari 488 GTE||LMGTE PRO||31.194|
|16||95|| Marco Sorensen
|Aston Martin Vantage||LMGTE PRO||34.878|
|17||97|| Darren Turner
|Aston Martin Vantage||LMGTE PRO||1'50.831|
|18||91|| Richard Lietz
|Porsche 911 RSR||LMGTE PRO||26 laps|
|19||67|| Harry Tincknell
|Ford GT||LMGTE PRO||1'11.110|
|20||66|| Stefan Mücke
|Ford GT||LMGTE PRO||1'40.235|
|21||98|| Pedro Lamy
Paul Dalla Lana
|Aston Martin Vantage V8||LMGTE AM||30 laps|
|22||61|| Matt Griffin
Mok Weng Sun
|Ferrari 488 GTE||LMGTE AM||50.059|
|23||54|| Francesco Castellacci
|Ferrari 488 GTE||LMGTE AM||33 laps|
|24||77|| Christian Ried
|Porsche 911 RSR (991)||LMGTE AM||45 laps|
|25||86|| Michael Wainwright
|Porsche 911 RSR (991)||LMGTE AM||100 laps|
|26||25|| Vitaly Petrov
|Oreca 07||LMP2||141 laps|