Audi Sport Abt Schaeffler's Daniel Abt topped practice one in preparation for the Mexico City E-Prix, heading Venturi Formula E's Edoardo Mortara in the opening session of the weekend.
Abt, who secured a podium finish at the Santiago E-Prix last month, set a best time of a 59.319s lap, lapping the 2.093km-long Autodromo Hermanos Rodriguez circuit in under one minute, beating Mortara to the fastest time of the session by only 0.078s.
Alexander Sims was third fastest for BMW i Andretti Motorsport, trailing Abt by 0.120s while Season Two champion Sebastien Buemi was fourth, only 0.033s behind the third-placed Briton.
NIO Formula E's Oliver Turvey completed the top five, 0.167s adrift of Abt's session-topping pace while Lucas di Grassi was sixth fastest in the second works Audi, 0.294s adrift off his team-mate.
Using a customer Venturi VFE05 car, Stoffel Vandoorne ended FP1 in seventh fastest for HWA Racelab, closely followed by Antonio Felix da Costa in the second BMW, 0.023s behind the Belgian.
Sam Bird was the fastest Envision Virgin Racing driver in ninth while Jose Maria Lopez completed the top 10 for GEOX Dragon.
Pascal Wehrlein fronted an 11-12-13 for Formula E's rookies, with the German driver fronting the second half of the field, followed by Felipe Nasr and Oliver Rowland.
Robin Frijns, who experienced a scrappy FP1 session, characterised by a spin and a number of offs in Turn 1, was 14th fastest in the second Envision Virgin while Nelson Piquet Jr was 15th for Jaguar Racing.
Andre Lotterer was 16th fastest after having three offs in Turn 1, heading Tom Dillmann, reigning champion Jean-Eric Vergne, Mitch Evans and Gary Paffett who completed the top 20, despite crashing his HWA Racelab car with five minutes of running remaining after slapping the wall on the entry to Turn 14.
Second-placed championship man Jerome d'Ambrosio was 21st fastest for Mahindra while Felipe Massa completed the field, 1.294s off the pace.