Lucas Di Grassi saw his victory in the inaugural Mexico City ePrix at the Autodromo Hermanos Rodriguez chalked off after his Abt Schaeffler car was found to be below the legal weight limit following a frantic and, at times, chaotic 43-lap race.
Race organisers confirmed hours after Di Grassi took the chequered flag that he had been excluded from the result due to his car weighing 886.2kg, 1.8kg below the limit of 888kg. The decision elevated D'Ambrosio to race winner, while second-placed Sebastian Buemi now retains his championship lead, building a 22-point advantage over Di Grassi in the process.
The 31-year-old Brazilian started third on the grid behind pole-sitter Jerome D’Ambrosio and Nicolas Prost, but he surprised the Frenchman the lap before the top four pitted to move up to second.
With the pit lane springing into life, D’Ambrosio re-emerged in the lead ahead of Di Grassi, though Buemi had leapfrogged his Renault e-Dams team-mate Prost as the pair emerged from the garage, with the son of the four-time Formula One world champion, Alain Prost, later hit with a drive-through penalty that would seem to wreck his chances of a podium finish.
Loic Duval, who originally finished fourth and was expected to join D'Ambrosio and Buemi on the rostrum, was hit with a 15-second time penalty for repeatedly cutting chicanes, and Prost benefitted as a result to finish third ahead of Duval. Prost also claimed the two extra points for fastest lap after D'Ambrosio's effort was excluded for cutting the chicane.
After pitting on lap 23, Di Grassi emerged from the final turn lining up D’Ambrosio for the lead, and utilised the Fan Boost that he had been awarded alongside Jean-Eric Vergne and home favourite Salvador Duran to lunge up the inside of the Swiss and take a lead that he would not relinquish.
However, as Di Grassi made a break at the front, chaos would ensue behind. Buemi had dominated both practice sessions on Saturday morning only to make yet another qualifying error that saw him start the race fifth. Having passed Daniel Abt early on and Prost in the pits, he fancied his chances at conquering D’Ambrosio, but made a huge error at the start of the 29th lap as he veered straight into D’Ambrosio as they crossed the finish line.
Six laps later, Buemi would attempt to take second with a move around the outside into the first chicane. D’Ambrosio closed the door on the Frenchman, forcing him to cut the corner and overtake Buemi illegally.
After holding position for the majority of the lap, Buemi attempted to let D’Ambrosio through as they came out of the stadium section, only for Prost to complicate the matter by passing an incensed D’Ambrosio. Voicing his anger in a foul-mouthed outburst on his team radio, D’Ambrosio drove straight through the final chicane, passing both Prost and Buemi to reassume second position, giving the race stewards a major headache in the process.
The bickering behind allowed Di Grassi to build a 3.5 second lead, and he would stretch it to over five seconds when he crossed the finish line to take his fifth career Formula E victory.
Buemi pushed D’Ambrosio right to the very end as the pair crossed the line alongside one-another, but it was the Dragon Racing man who clinched provisional second, leaving Buemi to stew in his cockpit as he finished an agonising third before moving up due to Di Grassi's exclusion.
Abt’s crash on the penultimate lap allowed Duval to finish fourth - where he would remain in the confirmed results - with Robin Frijns making a late move past Britain’s Sam Bird to seal what would become fifth.
The result means that Di Grassi trails Buemi in the drivers’ standings by 22 points, with the Frenchman leading the way on 98 points with Di Grassi second on 76 points and Bird trailing in third with 60 points..
With the 33,319-strong crowd creating an incredible podium ceremony in the heart of the stadium section that race-winner Di Grassi admitted was “the craziest of my life”, Formula E could be credited with being a phenomenal success among fans who have a long and passionate history with motorsport, although the fallout continued after the race. Buemi accused D’Ambrosio of deliberately closing the door on him when the pair collided, despite replays appearing to show the e-Dams driver turning into D’Ambrosio, and he also criticised the layout of the track for hampering overtaking.
“My idea was always to try and exit as quickly and possible from the final corner,” said Buemi. “The layout here is not very good, they take away the chances to overtake and they need to work on it for next year. I’m all for closing the door, that’s part of racing, but I had my nose alongside him and he shouldn’t have closed the door.
He added in his criticism of the track: “I think today we were not quick enough to be honest. It’s a very strange track here, the altitude and the asphalt was hot, so I’m looking forward to going back to a normal city circuit.”
However, a beaming Di Grassi enthused that the event had been a success and thanked social media users for giving him the Fan Boost that helped him to provisional victory, accepting that the layout of short straights and three tight chicanes had also helped him to pull away from the Renault e-Dams of Buemi given he was unable to utilise its superior straight line speed.
“First of all I’d like to say thank you to the Mexican people,” said Di Grassi. “Secondly, yes Fan Boost did help me win the race. I managed to pass Nico before the pits for second, and then with Fan Boost I was able to pass Jerome.
“I’d like to thank everyone who voted for me for Fan Boost.
“After I got Jerome, I did three laps with more energy than I could, and I could see Seb was trying to pass him, so I was looking at the big screens to see where they are, and then they disappeared.”
The next race takes place at Long Beach, California, on 2 April.