A violent crash that left reigning champion Pascal Wehrlein trapped upside down in his Porsche was just part of the drama in a wild Formula E season-opener in Sao Paulo, won by Mitch Evans from the back of the grid.

WEHRLEIN'S FRIGHTENING CRASH

Wehrlein was sent flying into the wall by Nick Cassidy's damaged Jaguar moments after Cassidy had clashed with DS Penske driver Maxilimilian Guenther in a frenetic lead pack.

A look at the incident between Wehrlein and Cassidy that brought out the red flag