Daniel Abt headed team-mate Lucas di Grassi at the end of the morning session of Formula E's third and final in-season group test at the Autodromo Hermanos Rodriguez circuit in Mexico City.
Abt, who completed 52 laps in the three-hour session, set a best time of 58.917s to top the timesheets, with di Grassi, who took his first win of the 2018/19 season in Mexico City yesterday, trailing his team-mate in the second Audi Sport Abt Schaeffler car by 0.045s.
Felipe Massa set the third fastest time in the session for Venturi, 0.060s off Abt's pace while Jose Maria Lopez was fourth fastest for GEOX Dragon, a further 0.026s behind the third-placed Brazilian.
Robin Frijns fronted an Envision Virgin Racing 5-6 in the session, with team-mate Sam Bird ending up with the sixth fastest time after completing 44 laps, ending up 0.209s slower than Abt.
Reigning Formula E champion Jean-Eric Vergne was seventh as the lead DS Techeetah car with team-mate Andre Lotterer ending up in ninth, the pair being separated by Nissan e.dams' Sebastien Buemi.
Stoffel Vandoorne completed the top 10 for HWA Racelab, 0.435s off the pace and was followed by BMW i Andretti Motorsport's Alexander Sims, with the Briton setting the 11th fastest time to outpace Felipe Nasr in the second Dragon and Antonio Felix da Costa who was 13th.
Oliver Rowland, who was in a strong position for a maiden podium finish at the Mexico City E-Prix before running out of energy, was 14th and was followed by reigning DTM champion Gary Paffett.
Panasonic Jaguar Racing's Mitch Evans headed Mexico City third-placed finisher Edoardo Mortara in 16th while Tom Dillmann was the lead NIO driver, ending up with the 18th fastest time.
Pascal Wehrlein was 19th in the Mahindra M5Electro, followed by Oliver Turvey, Jerome d'Ambrosio and Nelson Piquet Jr who completed the field with the least amount of running, only completing 23 tours of the 2.093km-long circuit in the second Jaguar I-TYPE 3.