Porsche topped the times in the opening session of the Le Mans test day.
Neel Jani set a fastest time of 3m22.334s during the first four hours of the official test for the Le Mans 24 Hours on June 18/19.
That time was just two tenths up on the second Porsche 919 Hybrid in which Mark Webber posted a 3m22.555s.
The best of the Audi R18 e-tron quattros was third fastest, a further two tenths behind on a 3m22.761s from Marcel Fassler.
That was just three hundredths ahead of Loic Duval in the second of the Audis.
The two Toyota TS050 HYBRIDs were fifth and sixth in the hands of Anthony Davidson and Kamui Kobayashi respectively.
Davidson brought Toyota to within a second of the pace with his final lap of the session, a 3m23.197 that left him eight tenths behind Jani.
Jani's fastest lap compares with the 3m21.061s that Porsche driver Brendon Hartley set to top the times at the test day last year and his own pole mark of 3m16.887s.
The LMP1 hybrids should be slower this year courtesy of a reduction of their per-lap fuel allocation of approximately 7.5 per cent.
The factory Porsche team was also quickest in GTE Pro.
Frederic Makowiecki's 3m55.691s put him just over half a second up on team-mate Kevin Estre in the second 911 RSR.
Oliver Gavin was just a tenth behind in the fastest of the Chevrolet Corvette C7.Rs.
LMP2 led was by Signatech Alpine driver Nicolas Lapierre.
He set a 3m37.397s aboard the best of the Signatech ORECA-Nissan 05s to end up a tenth of a second clear of the Eurasia team's example of the car in the hands of Tristan Gommendy.
Matt Griffin posted the fastest time in GTE Am in his AF Corse Ferrari 458 Italia.