Sebastien Buemi topped the first day of official Formula E testing at Donington Park on Thursday for the Alain Prost-associated e.dams squad.
The ex-Formula 1 racer, now a Toyota LMP1 driver in the World Endurance Championship, set the fastest time of 1m35.475s - on a modified track with an extra chicane after the Old Hairpin - in the final hour of the day.
"I'm more than happy to be honest," said Buemi. "It is always nice to be P1 and let's hope it continues tomorrow.
"I didn't have any problems with the car at all and that meant we were able to learn quite a lot about it."
The test marked the first significant dry running for the championship's teams, after last month's shakedown was run in wet conditions at the same track.
Lucas di Grassi was second fastest for the Audi-backed Abt team, having taken over driving duties from morning pacesetter Daniel Abt when the German departed for this weekend's GP2 round supporting the British Grand Prix.
Sam Bird, Bruno Senna and Stephane Sarrazin completed the top five, with Sarrazin declaring the feeling of the all-electric engine "completely new" compared to the hybrid-powered sportscars he has driven.
Despite only completing 11 laps Nicolas Prost made sure both e.dams cars were in the top six, just edging out grand prix winner Jarno Trulli's best effort, while Abt's morning benchmark was good enough for eighth overall.
The day did not run smoothly for all of the teams, as 12 seconds covered the 19 drivers that managed to set a time, and six of the 20 in attendance were more than five seconds adrift of Buemi's best.
Trulli's team-mate Michela Cerruti was unable to complete a lap due to technical problems, while Karun Chandhok - 10th fastest - only managed one lap in the afternoon due to an issue.
Pos Driver Team Time Gap Laps 1. Sebastien Buemi e.dams 1m35.475s 36 2. Lucas di Grassi Abt 1m36.012s +0.537s 29 3. Sam Bird Virgin 1m36.370s +0.895s 31 4. Bruno Senna Mahindra 1m36.385s +0.910s 22 5. Stephane Sarrazin Venturi 1m36.698s +1.223s 24 6. Nicolas Prost e.dams 1m36.707s +1.232s 11 7. Jarno Trulli Trulli 1m36.969s +1.494s 30 8. Daniel Abt Abt 1m37.212s +1.737s 32 9. Jaime Alguersuari Virgin 1m37.445s +1.970s 17 10. Karun Chandhok Mahindra 1m37.532s +2.057s 21 11. Franck Montagny Andretti 1m38.062s +2.587s 29 12. Antonio Felix da Costa Aguri 1m38.079s +2.604s 24 13. Jerome d'Ambrosio China 1m38.086s +2.611s 33 14. Antonio Garcia China 1m38.204s +2.729s 21 15. Nick Heidfeld Venturi 1m40.744s +5.269s 17 16. Mike Conway Dragon 1m41.168s +5.693s 16 17. Gil de Ferran Andretti 1m44.972s +9.497s 11 18. Scott Speed Andretti 1m45.909s +10.434s 6 19. Katherine Legge Aguri 1m48.296s +12.821s 11 20. Michela Cerruti Trulli 0