Wehrlein flew away from the second row of the grid to sweep around the outside of poleistter Guenther and P2 Barnard at the long, tightening right hander at Turn 1.
Standings leader Rowland, meanwhile made up five spots on Lap 1 to find himself second, ahead of Guenther.
The leaders squabbled hard with positions swapping through Lap 2 before it all got a bit too close through the chicane with Cassidy coming off worst – spat out into a half spin and down to the back of the field – Rowland, Guenther and Hughes somehow unscathed amid the crunching carbon fibre to lead the pack on Lap 4.
Vandoorne was first to jump for the initial of his two 50kW four-wheel driver Attack Mode boosts and clambered up to the front of the field come Lap 6, taking advantage of some minor contact between Hughes and Rowland which saw both stumble.
Positions cycled as energy usage came to the fore through the first third of the race, and Attack Mode started to come into play.
De Vries led di Grassi, Rowland, Guenther, Buemi, Vandoorne the top six on Lap 9 – while reigning champion Wehrlein slipped as far as 12th through the first round of Attack.
The Porsche driver made it back up to P5 come the end of his first 50kw boost, with Rowland and Guenther still to activate.
Rowland looked to be employing the same strategy as he did in Jeddah, during the first PIT BOOST race – going later for his first Attack to get to clear air out front before pitting, with leader de Vries covering that strategy off and matching the Brit up.
Mueller’s early leap for PIT BOOST left him well placed as he fired in the quick laps to go gain enough time on those yet to stop to leave him the net race lead as it stood.
Rowland and Guenther had to put their foot down to counter, and they duly did – doing just enough on Lap 18 to emerge from their stops out front.
A lap later, and Wehrlein, who had put pressure on the leaders prior to his PIT BOOST stop, then split Guenther and Rowland to emerge P2.
On lap 19, Robin Frijns, who’d quietly found his way through the pack to fourth, made a move on Rowland for third, as it stood – 13 places gained.
Those yet to use their final Attack Mode, and had energy in-hand then chose to leap. Barnard jumped the lead group to slice by the front-runners through the final chicane and away from the pack to the tune of almost two seconds on Lap 21 the NEOM McLaren driver dropping Guenther, de Vries and Wehrlein.
Guenther had half a minute of Attack over Rowland himself, and pressured the Nissan through the final laps before making a move count on Lap 26 over the start/finish.
On lap 27, Barnard produced a storming move on Rowland for second – hanging it around the outside of Rowland to steal up the inside of the Nissan into the chicane, with Ticktum following in the melee to clamber onto the final step on the podium.
On the final lap, Guenther was home and dry out front but behind it was all kicking off. Ticktum pressured Barnard, with a dive into Turn 1 followed a move at the chicane.
He leapt outside of Barnard while Vergne jumped inside the McLaren to bypass Ticktum in the process into second.
The full top 10 are- P1: Guenther, P2: Vergne, P3: Barnard, P4: Ticktum, P5: Rowland, P6: Nato, P7: Bird, P8: De Vries, P9: Buemi and P10: Frijns.