Dennis soaked in the adulation of the Foro Sol and the packed grandstands watching on, with some 40,000 ultra-passionate Mexican fans here to be a part of the first race of Formula E's latest generational leap. The Andretti driver made what would be the race-winning move on Lap 12, with the Brit taking advantage of an opening left by di Grassi.
From there, Dennis stretched his legs, and through three Safety Car periods, he was able to run away with the race lead - eventually heading home Wehrlein by a huge seven seconds. Wehrlein produced a storming drive himself.
Last year's winner here clearly enjoys the afternoon sun in Mexico City, and pulled out an eventual 11-second margin on third-placed di Grassi, having clambered up from sixth on the grid. The two Porsche-powered cars looked pretty much peerless - a good sign for the legendary Stuttgart manufacturer right from the off in GEN3, who finished up with four of their powertrains in the top seven.
Di Grassi had earlier taken Julius Baer Pole Position but found himself on the defensive from the two-thirds point of the race. He was a percent or so shy on usable energy compared to those immediately around him and it took all the Brazilian's guile to see off the attentions of NEOM McLaren's Jake Hughes over the closing stages.
Eventually, though, the rookie would be preoccupied with Lotterer looming in his mirrors, relieiving the pressure on di Grassi. Lotterer, who moved to the Porsche-powered Andretti team over the off-season, is notriously feisty and there was no way he'd settle for fifth. Duly, he spied his chance and threw it up the inside of Hughes' McLaren at the hairpin on the final lap.
Fifth was no disappointment for Hughes on debut; the rookie more than impressing ever since he jumped into the seat of his McLaren back at testing in Valencia. He headed home a resurgent Sebastien Buemi - the Swiss having moved from Nissan to Envision Racing over the winter and back on-song.
Season 6 champion Antonio Felix da Costa added to Porsche's tally with seventh spot on the day, fighting his way up throught the points-paying positions late-race with a belated dose of ATTACK MODE. Mitch Evans quietly strode to points and eighth for Jaguar TCS Racing, Nick Cassidy made it two Envision Racing machines in the points with ninth, while reigning champion Stoffel Vandoorne could only steer his DS PENSKE to a single point from 14th on the grid.
For good measure, Dennis sealed the TAG Heuer Fastest Lap, too.
Formula E is back in a fortnight with a double-header - a pair of night races in Diriyah, Saudi Arabia on 27 & 28 January.
As it happened...
Di Grassi got away cleanly as the pack launched for the first time in Season 9. As did Hughes but Dennis held fast in second and fended off the McLaren’s advances.
The field filtered through the first few turns but Robin Frijns’ ABT CUPRA was one that didn’t make it, throwing an early Safety Car, with the Dutchman running into the back of Norman Nato’s Nissan at Turn 9. That removed the Frenchman from proceedings in the process, and unfortunately injured the ABT driver; breaking his wrist.
Lap 6 of 36 saw the restart, with the Porsche Taycan Safety Car peeling away into the pits to release leader di Grassi, Dennis, Hughes, Lotterer, Ticktum, Wehrlein, Fenestraz, Buemi, da Costa and Evans the top 10. Back into the groove for the pack.
Sam Bird had earlier said he didn’t think anything else could possibly go wrong in Mexico but on Lap 7 his Jaguar ground to a halt with another technical issue, on the inside of Turn 2. Not the start to Formula E’s third era the Brit would have wanted.
Green flag once again, on Lap 10, and it was you were at the front with di Grassi leading Dennis by half-a-second – three Porsche-powered cars in the top five.
ATTACK MODE this year is even more strategic with 350kW available for four minutes in two intervals. The drivers and strategists can decide to split it across two activations lasting two minutes, a one plus a three minute activation or a three plus a one minute burst.
Cassidy and reigning champion Vandoorne were first to jump for their initial boost – the latter going for a three plus one minute split as he seeks to recover from a disappointing qualifying session. Instant progress, as he leapt by the Envision Racing driver for 13th.
All change at the front on Lap 12. Dennis looked to have caught di Grassi napping at Turn 3, diving up the inside of the Mahindra and making it stick after the then-leader had run wide through Turn 1. Hughes tried to follow but the Brazilian did close the door. Meanwhile, a power spike for Ticktum sent the NIO tumbling down the order following a penalty – super disappointing after such pace and promise all weekend.
Dennis started to stamp his authority on things with the TAG Heuer Fastest Lap up to this point on Lap 14, helping open a 1.5s gap on second-placed di Grassi. Behind, Hughes, Wehrlein, Lotterer and Sacha Fenestraz (Nissan) jumped for ATTACK MODE. The DS’ were quietly making progress with Jean-Eric Vergne (DS PENSKE) 10th and in the points with Vandoorne now just behind in 11th.
Through that first round of ATTACK MODE, Dennis pulled out some four seconds on the rest come Lap 18 – properly commanding, with the rest struggling for an answer.
Another Safety Car was required on Lap 19 with Edo Mortara’s Maserati MSG Racing Tipo Folgore pirouetting backwards into the Turn 1 wall and out – that made it four pointless races in five for Mortara.
Lap 22 saw the Green Flag fly again with the top four running as was: Dennis, di Grassi, Hughes and Wehrlein. Come Lap 26, Dennis had stretched his legs by more than two seconds over the rest and looked properly switched on.
The second round of ATTACK MODE boosts saw Wehrlein and Lotterer jump from fourth and fifth as they set about closing on the lead quartet. Di Grassi and Hughes followed a lap later but the McLaren driver couldn’t hold the Porsche off, with Wehrlein clambering onto the podium as it stood. Dennis’ trip through the activation loop was far more uneventful – a lead of four seconds on Lap 28.
On Lap 29, Wehrlein jumped di Grassi into the chicane, the Mahindra looking more marginal on energy and unable to put up a fight – a Porsche powertrain one-two.
Five laps were added on for time lost under the Safety Car, and it looked Dennis’ to lose. Wehrlein was comfortable in second and di Grassi was left clinging to third under pressure from Hughes – the Brazilian fast in all the right places to defend from the papaya machine.
The battle for third, fourth and fifth between di Grassi, Hughes and Lotterer was where it was at as the laps ran down. By the fourth added lap of five, Buemi in sixth and da Costa in seventh had joined the party but in the melee, the Mahindra at the head of the queue had strung out almost a second – some defense.
Lotterer had been aching to pinch fourth from Hughes and did it at the hairpin on the last lap.
Dennis headed home Wehrlein, with the Porsche-powered pair flying clear of the rest. Di Grassi held onto third to round out the podium.