Mortara had overtaken Venturi teammate Lucas di Grassi at Turn 18 amid a furious battle among the front-guard runners, and then had to hold off the advances of Frijns – who had swept past di Grassi on lap 29 in his bid for victory.
But a late safety car for the stricken Mahindra of Alexander Sims, who hit the wall at Turn 6 and came to a stop, bunched up the field – arguably more than expected, as the field was momentarily stopped at the top of the hill as the safety car waited for the recovery vehicle.
But as the clock ticked past the 41-minute threshold, no time was added on – and the slow progress of clearing Sims’ car at the top of the circuit gave no opportunity for anything other than a last-corner dash to the finish – which Mortara easily navigated for his third Formula E victory.
Mortara had started alongside polesitter Nyck de Vries on the grid, but the Dutchman held on into Turn 1 and looked likely to put together two successive victories having won yesterday’s race at Diriyah.
De Vries navigated the first flurry of attack mode uses, leading Mortara and di Grassi through the activation zone to remain ahead.
But di Grassi went for an early second activation, taking his hit of extra power on lap 12 and undercutting Frijns – who tried to cover him off a lap later.
Mortara followed suit, falling behind di Grassi, but de Vries elected to save his own attack mode – leaving him vulnerable to their advances with a 30kW deficit.
Di Grassi then pulled a move on de Vries heading into Turn 18, attempting to take the outside line, but de Vries got on the brakes later and tried to bat the 2016-17 champion away.
The two ended up making contact twice at the chicane, with di Grassi barging his way back past after both were left on the run-off, claiming the lead for his efforts – albeit with an FIA investigation looming over the move.
Mortara then cleared de Vries on the following tour, albeit more cleanly than his teammate could manage, as de Vries continued to resist the urge to join them on attack mode.
The Venturis then effectively switched places, as Mortara put a move on di Grassi to claim the lead.
Although Frijns began to give chase, the Envision driver was momentarily preoccupied with the chasing pack of Andre Lotterer, Jean-Eric Vergne and Jake Dennis – losing a place on lap 18 as Lotterer threaded his car nearly on the brakes to sit between Frijns and de Vries ahead.
Frijns repassed Lotterer two laps later, their battle giving de Vries some breathing space – albeit not enough to retain third when the Mercedes finally took attack mode on lap 22.
But de Vries, unable to put a cohesive move on Frijns, soon watched Jean-Eric Vergne draw nearer in his mirrors – and Vergne was robust in his efforts to pass de Vries at the favoured Turn 18 spot, getting the switchback as his rival went deep into the braking zone and swiping across into the following corner.
This put de Vries in a compromised position for the following corners, leaving him a sitting duck for Lotterer, Dennis, teammate Stoffel Vandoorne and Oliver Rowland.
Frijns’s move on di Grassi was good enough for second place, as di Grassi ensured two Venturi drivers made it onto the podium.
Lotterer got past Vergne to grab fourth, suffering no repeat of the energy management issues that left him struggling in the first race, and Dennis followed Lotterer through to grab fifth.
Vergne finished sixth ahead of Vandoorne, who recovered from getting knocked out in the group phase of qualifying to finish seventh, with Rowland in close pursuit.
Wehrlein put a further move on de Vries to compound the reigning champion’s misery, claiming ninth to ensure both Porsches made the points.
Mitch Evans missed out on points, as did impressive rookie Oliver Askew – who won out in a phenomenal race-long battle with Antonio Felix da Costa.