Techeetah’s Vergne, who had fought his way back to 10th after setting the fastest lap, clashed with former Formula One ace Felipe Massa on the last lap of the 1.4 mile street circuit in Brooklyn and finished out of the points.
His misfortune has opened the door for Brazilian Lucas di Grassi, who finished fifth after charging through the field from 14th on the grid, second-placed Mitch Evans of New Zealand and Swiss Buemi, the championship winner in the 2015-16 season.
Vergne, who looked assured of the title going into the two season-ending races in the Big Apple, still leads di Grassi by 22 points, with a maximum of 29 available each race, with Evans three further adrift and Buemi in fourth place, 26 points adrift.
Buemi (Nissan e.dams) had qualified fastest, earning three points, in search of an elusive 13th victory in Formula E, and led throughout despite coming under strong pressure from Britain’s Alex Lynn (Jaguar Racing), who was later forced to retire.
Behind him, Vergne, who qualified a lowly 10th, was clipped from behind by his teammate Andre Lotterer in an early incident, forcing both to pit with the title leader dropping to 19th
A late yellow flag left him with a chance to work his way through the field to pick up crucial points until in attempting to overtake Venturi driver Massa he lost a wing and limped over the line in 15th and out of the points.
Buemi is the ninth different winner in 12 rounds of a topsy-turvy 2018-19 season after a race being lauded as one of the most exciting in the history of the Formula E championship.
“It’s an amazing feeling, it’s a been a hard season and it finally happened today,” he said.
Evans, who also started way back on the grid in 13th, steadily worked his way through the field, showing the same pace as his Jaguar Racing teammate Lynn to claim an unexpected runner-up spot.
Antonio Felix Da Costa of Portugal took the final podium place for the BMW Andretti team.
But it is Audi Sport’s di Grassi who has been left with the best chance of overhauling Vergne after gaining 10 valuable points.
However, with Vergne still having a commanding lead, di Grassi knows there is a tough task ahead.
“We need to improve for sure,” he said.
His team will also be hoping to claim the constructors’ crown after cutting Techeetah’s lead in that title race to just 24 points with all still to play for in Sunday’s 13th and final round of a compelling championship.