The No. 8 Audi R18 leads the FIA WEC Six Hours of Mexico presented by AT&T, with one hour complete, and under a Full Course Yellow.
Lotterer holds a 12-second lead over the No. 1 Porsche 919 Hybrid of Mark Webber, who took over second after an early pit stop for the No. 7 Audi of Andre Lotterer at the 42-minute mark.
A FCY, for a crash by the No. 37 SMP Racing BR Engineering BR01 Nissan of Victor Shaytar, eight minutes later, saw the majority of cars take advantage of the slowed pace and pit for service.
While Audi has held the edge so far, the No. 5 Toyota TS050 Hybrid of Kazuki Nakajima runs in third, ahead of the No. 2 Porsche of Neel Jani in fourth.
A spin by Mike Conway, while under FCY, has dropped the No. 6 Toyota to sixth.
The No. 26 G-Drive Racing Oreca 05 Nissan of Roman Rusinov leads LMP2, with the Russian squad getting out ahead of the class pole-sitting No. 43 RGR Sport Ligier JS P2 Nissan, which dominated early in the hands of Bruno Senna.
Marco Sorensen is out front in GTE-Pro in the No. 95 Aston Martin Vantage GTE, with the No. 88 Abu Dhabi Proton Racing Porsche of Khaled al Quabasi leading GTE-Am.
Rain has yet to hit, although there remains a chance of thunderstorms later this afternoon.