For Toyota, Stephane Sarrazin joined battle with Hartley. The pair took turns at the front between their stops before Sarrazin crucially pulled off a 15-second stop to go into a five second lead during a pitstop cycle.
The Toyota TS040's position at the front then became even more secure, as Hartley had to make an unscheduled stop with what he suspected was a puncture.
Benoit Treluyer came up to second in the #2 Audi R18 e-tron quattro, while Hartley briefly lost third to the #1 Audi of Lucas di Grassi - which passed the Porsche with ease on the start-finish straight before pitting shortly afterwards.
Treluyer was unable to match Sarrazin's pace, allowing the Toyota to extend his lead to more than 50 seconds towards the end of the hour.
At hour six, Toyota continued to lead the race with Stefane Sarrazin in the leading No.7 car. Sarrazin had edged the leading TS040 HYBRID's advantage up to one minute over the No.2 Audi R18 e-tron quattro of Benoit Treluyer, but that was reduced by around 25 seconds when Toyota decided against that strategy, instead putting on fresh tyres as Kazuki Nakajima took over from Sarrazin towards the end of the hour.
Brendon Hartley's Porsche 919 Hybrid and Lucas di Grassi's Audi traded places depending on their pitstops, with the #20 919 being out of sync after stopping with its suspected puncture earlier in the race. Hartley went off toward the end of his stint and Mark Webber has now taken over the No. 20 car.
The race heads into the dark - but even at 10pm, there is still a twilight look to the sky due to the longer days of the northern hemisphere summer.