Di Grassi became the third champion in three seasons of the electric single-seater series as title rival Sebastien Buemi endured a terrible race. 

Buemi’s 13th-place start put him in the firing line at the start for the second time this weekend, and he picked up rear bodywork damage when the pack concertinaed at Turn 1 after Stephane Sarrazin spun following contact from Daniel Abt. 

That meant Buemi was flagged into the pits for repairs, and although the offending part fell off his Renault e.dams he was still forced to stop.Buemi had made up two places before doing so but the impromptu trip to the pitlane ruined his race and made a difficult task almost impossible. 

Though he charged back up the order, Buemi finished a point-less 11th, and his misfortune allowed di Grassi to coast to the end of the race. 

Title glory for di Grassi

The Brazilian was aggressive when required, though, after dropping to 10th at one stage. He fought back to sixth, then handed the position to team-mate Abt on the final lap and clinched the crown at the third attempt in seventh place. 

Di Grassi – who finished third in the first season and second, behind Buemi, in 2015/16 – was in tears on his inlap, after snatching a title that seemed destined for Buemi until this final weekend. 

Buemi’s disqualification on Saturday, having risen to fourth from 12th on the grid, and a poor qualifying performance for the final race meant di Grassi turned a 10-point deficit coming to Montreal into a comfortable, 24-point winning margin.

The swinging title fortunes detracted attention from Vergne’s first win in FE, a feat he has been waiting to achieve since claiming pole on his debut in round three of the inaugural campaign. 

Vergne thwarts Rosenqvist

Vergne had to catch and pass poleman Felix Rosenqvist in the second half of the race, after the Mahindra driver stopped a lap earlier than his pursuer to swap cars. 

That gave Rosenqvist a five-second lead once Vergne stopped but also meant he had to go a lap longer in his second car, and Vergne gradually ate into the advantage.  

He took the lead with a relatively simple move and eased clear to score his and Techeetah’s first victory in FE. 

Rosenqvist briefly came under pressure from Jose Maria Lopez for second after the DS Virgin Racing driver charged from 11th on the grid. 

Lopez faded on the penultimate lap though, leaving Mahindra’s Rosenqvist to secure third place in the drivers’ championship in his rookie season. 

Sam Bird finished fourth behind team-mate Lopez, with Nick Heidfeld fifth in the second Mahindra. 

Sarrazin recovered from his first-corner spin to claim eighth with a fighting drive, while Jerome d’Ambrosio and Tom Dillmann completed the point scorers.

Pos	Driver	Team	Time/Gap
1	Jean-Eric Vergne	Techeetah	54'12.606
2	Felix Rosenqvist	Mahindra Racing	0.896
3	Jose Maria Lopez	Virgin Racing	4.468
4	Sam Bird	Virgin Racing	7.114
5	Nick Heidfeld	Mahindra Racing	21.933
6	Daniel Abt	Team Abt	24.444
7	Lucas di Grassi	Team Abt	24.855
8	Stéphane Sarrazin	Techeetah	26.038
9	Jérôme d'Ambrosio	Dragon Racing	28.282
10	Tom Dillmann	Venturi	28.591
11	Sébastien Buemi	DAMS	35.170
12	Mitch Evans	Jaguar Racing	36.548
13	Robin Frijns	Andretti Autosport	36.826
14	Adam Carroll	Jaguar Racing	36.972
15	Antonio Felix da Costa	Andretti Autosport	39.720
16	Nelson Piquet Jr.	NEXTEV TCR Formula E Team	46.751
17	Oliver Turvey	NEXTEV TCR Formula E Team	49.116
18	Maro Engel	Venturi	1'33.530
19	Loic Duval	Dragon Racing	3 laps
Ret	Nicolas Prost	DAMS	5 laps