Nick Cassidy ended Saturday's New York E-Prix in the wall following a sudden downpour, but the Envision Racing driver was nevertheless awarded his maiden Formula E victory.
Cassidy aquaplaned off the track along with several other drivers as the race entered its final ten minutes, with the commotion bringing the event to a premature halt and the Kiwi declared the winner on count-back.
From pole position, Cassidy led the field around the Brooklyn Street Circuit, followed by Mercedes-EQ's Stoffel Vandoorne, but the Belgian was overhauled in short order by Venturi's di Grassi and Nissan's Sebastien Buemi.
Meanwhile, title contender Jean-Eric Vergne suffered a major set-back when he spun and lost 30 seconds on the pack.
As positions rotated in phase with the race's first of two Attack Modes, di Grassi was the last man to charge up, but the Brazilian couldn't keep Cassidy behind while Vandoorne slipped down the order to fifth.
The Mercedes driver was able to make up a spot on Buemi during the second Attack Mode period and progress to third on lap 20 of 29. Vandoorne then gained another position to the detriment of Edoardo Mortara and sought to reel in Cassidy.
But an incisive di Grassi caught and overtook Vandoorne who also succumbed to a move by Robin Frijns.
However, as the race entered its final 15 minutes, the heavens above Brooklyn opened up and drenched the track and the drivers, especially at the end of the back straight on the approach to Turn 6.
The leaders hit the passive puddle first and spun out of control, with Cassidy and di Grassi hitting the barriers while Frijns and Mortara made their way through.
With conditions no longer safe, race control brandished the red flag and applied a countback to the previous completed lap that delivered the win to Cassidy from di Grassi and Frijns.
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