A heavy rain shower just 30-minutes before the start of Free Practice 1 gave the competitors some tricky conditions to contend with in the opening session of the weekend.
On a wet track the no1 Porsche LMP Team 919 hybrid of Andre Lotterer was the quickest car in the first practice session of the 6 Hours of Mexico weekend.
The German driver set a lap of 1m27.026, six tenths ahead of the no2 Porsche of fellow German Timo Bernhard.
The two Toyotas were third and fourth quickest with the no7 TS050 the fastest, two seconds behind the lead car.
The no36 Signatech Alpine Matmut A470-Gibson of Nico Lapierre was the quickest of the nine LMP2 entries with the French driver setting a 1m34.556.
The lap was less than four tenths ahead of the two Vaillante Rebellion Oreca 07s, with the no13 car setting the second best time of the 90-minute session with a 1m34.932.
In LMGTE Pro it was Ferrari ahead of Porsche ahead of Aston Martin with James Calado setting a class best of 1m41.101 on the drying track in the no51 AF Corse F488.
The no91 Porsche 911 of Fred Makowiecki was second quickest, 0.076s behind the lead Ferrari and 0.120 ahead of the no95 Aston Martin Racing Vantage of Nicki Thiim.
The no77 Dempsey Proton Racing Porsche 911 of Matteo Cairoli was fastest in the LMGTE Am class with a 1m42.469 ahead of the second Porsche 911, the no88 Gulf Racing entered car of Ben Barker, who set a 1m42.576, 0.107s behind the lead Porsche and 0.347s ahead of Pedro Lamy in the no98 Aston Martin Racing Vantage.
The second Free Practice Session of the 6 Hours of Mexico weekend will take place tomorrow at 09h30 (local) / 16h30 CET.