Cassidy, who finished third in the opening race in Saudi Arabia, took the lead as early as lap five having started third on the grid.
He retained his position at the head of the field even when taking both his Attack Mode activations before managing the remainder of the 36-lap race to head home Envision’s Frijns and Nissan’s Oliver Rowland.
Polesitter Rowland initially launched well off the line at the start, but bogging down in the second phase of acceleration allowed fellow front row starter Frijns to pull alongside and take the lead into the opening turn.
The Nissan driver lost a further position to Cassidy on lap four as he took the first of his Attack Mode activations and began to gradually drop away from the leading pair.
This allowed Frijns to relinquish the lead to Cassidy a lap later but only drop to second, as Cassidy began to increase the pace at the head of the field in order to build a gap to the Dutchman behind.
Cassidy had built up a 1.6s advantage to Frijns, which would likely have been enough to retain the lead when taking his first Attack Mode, but he maintained the same gap as Frijns took his second activation at the same time on lap seven.
When Cassidy took his final Attack Mode on lap 13, he comfortably retained the lead having built a gap of almost 2s before he began to slow his pace and back Frijns into the chasing pack.
This was headed by Rowland, McLaren’s Jake Hughes, DS Penske’s Stoffel Vandoorne and the second Nissan of Sacha Fenestraz, with the top six having taken both Attack Mode activations by half distance.
Source: Autosport