Brendon Hartley is leading the Six Hours of Mexico presented by AT&T at the halfway point, but Loic Duval is only seven seconds behind the No. 1 Porsche 919 Hybrid.
It comes as the track has been declared wet, with adverse weather conditions expected to affect the FIA World Endurance Championship’s first visit to Autodromo Hermanos Rodriguez.
The leading pair of Hartley and Duval are at the wheels of the two most competitive cars so far, but the entire LMP1 class has seen some close racing so far.
So far the only major issue had by any of the top teams was a hybrid problem for the No. 5 Toyota TS050 Hybrid, which retired in the third hour.
The RGR Sport Ligier JS P2 Nissan, which started from LMP2 pole, dropped to third after contact with the G-Drive Racing Oreca 05 Nissan.
Stephane Richelmi currently leads the class in the No. 36 Signatech Alpine A460 Nissan.
Aston Martin Racing has dominated the GTE-Pro class thus far, with the pair of Aston Martin V8 Vantage GTEs running 1-2 for the first three hours. Nicki Thiim currently leads the category.
David Heinemeier Hansson is the GTE-Am leader. His Abu Dhabi Proton Racing Porsche 911 RSR inherited the lead from the Gulf Racing car during the first round of pit stops.
The field came out of a short Full Course Yellow just before the three-hour mark, called to remove debris from the track.