Dennis survived two missed trips through the ATTACK MODE loop, heavy pressure from his closest rival and polesitter Nick Cassidy (Envision Racing) as well as two Red Flags to become Formula E's first British World Champion and the first to take the title on home soil - all while sealing record 10th podium of the season. Dennis' title is also Andretti's first in Formula E - the American team having been a part of the series from day one.
Dennis headed into the race 24 points clear of Nick Cassidy (Envision Racing) - who started from pole.
The Kiwi led the early stages before ceding top spot to eventual winner and countryman Evans on Lap 11 and second spot to teammate Sebastien Buemi. Dennis had earlier made it by Cassidy with an opportunistic move at the final corner just a couple of laps before, with Cassidy immediately fighting his way back by the Andretti - a titanic scrap looked to be brewing.
However, with Cassidy running in formation, close-behind the Swiss, the Envision drivers came into contact. The former's front wing was dislodged, catching beneath his left-front wheel. Repairs were attempted but his race couldn't be salavaged - one fewer challenger for Dennis to deal with.
Loose bodywork from that clash caused a brief spell under the Safety Car, bunching the pack up. Dennis, meanwhile was not impressed over the radio with Porsche stablemate Pascal Wehrlein (TAG Heuer Porsche) - the German hanging onto fourth at the expense of the standings leader in the customer, Porsche-powered Avalanche Andretti as the Teams' title battle heated up.
Wehrlein's challenge then also fell by the wayside in a shunt just before a Red Flag was flown for the recovery of Sacha Fenestraz's Nissan. He and Jake Hughes tangled into Turn 1, with the damage to the German's Porsche terminal.
On the restart Evans led away, with Dennis working his way into third - enough to seal the title as it stood. An over-optimistic move from Norman Nato (Nissan) at the penultimate turn on Lap 34 caused a chain reaction behind with several cars unable to avoid the melee, enforcing another spell under Red Flag conditions.
It was three lap sprint to the flag at the restart with Dennis having only to hold fast to ensure he'd take top honours. Duly, he did, in front of a jubilant home support - made doubly sure by his promotion to second at the flag, just behind Evans, with a penalty for TAG Heuer Porsche's Antonio Felix da Costa dropping him out of the podium positions. Sebastien Buemi (Envision Racing) rounded out the podium.
All that saw Dennis crowned Drivers' Champion on 213 points, with Evans on 176 unable to catch him with one round from London on Sunday remaining of Season 9.
It's all still to play for in the Teams' running with Jaguar TCS Racing ahead of customers Envision Racing on wins alone, level on 268 points, with TAG Heuer Porsche clinging on in third with 241 while Avalanche Andretti sit fourth on 236 points.
Dennis: 'World Champions, baby!'
"Oh my God. That is incredible," said Dennis immediately post-race. "That race was so hard, everything thrown at us. World Champions, baby. I feel incredible, amazing.
"I felt like everyone was racing against us but Jesus Christ, we have just become World Champion and I am so so happy for myself, the team and everyone, we deserved it so much.
"I only joined the championship three years ago and we almost won it in our rookie year, but now to come back and properly have the year that we had, you know break all the podium records and to become World Champion, it’s just mind blowing. I really didn’t think it coming into this year and full credit to my boys - I love them so much and they've given me an absolute rocketship all year. And this is the least I can do for them.
"I can hear the fans as well and it's just absolutely incredible to share this with them, and my mum's out there somewhere too. World Champions - I am just amazed."
As it happened...
Off the line Buemi jumped Dennis to make it an Envision Racing one-two at the end of Lap 1, with polesitter Cassidy leading his teammate and the standings leader out into the East London sunshine.
On Lap 2, Evans held sixth with a sharp bit of defensive work through Turn 2 as Wehrlein looked to take back his position. The Kiwi then made it past Ticktum for fifth – strong and vital progress for the Jaguar driver.
Heading into Lap 4 and Cassidy headed Buemi, Dennis, Rast, Evans, Wehrlein, Ticktum, Bird, Nato and Vandoorne, rounding out the top 10 - all split by just four seconds.
With his teammate in second spot, Cassidy knew he could make the move his first of two mandatory 50kW ATTACK MODE boosts with no worry of his closest rival Dennis profiting. Buemi carried out his rear-gunner duties perfectly as the Kiwi jumped for a two-minute dose of ATTACK MODE - the first of the leaders to do so. On Lap 7, he took the remaining six-minute 50kW jolt, which did drop him behind both his teammate and Evans to third while the latter made it by Dennis, who missed the activation zone for his first ATTACK MODE boost.
Buemi then leapt for ATTACK MODE on Lap 9, briefly ceding the lead to Evans before an almighty scrap between Cassidy in third, Dennis in fourth and Rene Rast (NEOM McLaren) in fifth. Into the penultimate corner, the Brit made a super-brave move to catch Cassidy unawares and slip up the inside of the Envision into the final corner. Rast was able to pick both off as they scrabbled, though - the McLaren driver taking third, then second from Buemi later around that same lap.
It wasn't over, though. On Lap 12, Cassidy fought back as Buemi backed the Andretti driver up into his teammate's grasp. The elbows were firmly out from both but it was Cassidy who stuck to the inside line in Turn 3 to make a three-corner move stick.
An already-dramatic race then kicked up a notch further as Dennis' closest rival Cassidy fell from contention - his front wing coming unstuck after earlier contact with teammate Buemi, trapping itself beneath his front wheel and requiring a trip to the pits.
Loose bodywork on-track then saw the Safety Car appear on Lap 16, bunching the pack up. Dennis was not impressed over the radio with Porsche stablemate Wehrlein - the German hanging onto fourth at the expense of the standings leader in the customer, Porsche-powered Avalanche Andretti.
On the restart, Evans led Buemi, Rast, Wehrlein, Dennis, Bird, Guenther, Vandoorne, da Costa and Ticktum - while Cassidy was able to rejoin after running repairs to his car's nose in 18th position.
ATTACK MODE number one was yet again elusive for Dennis as he missed the loop for a second time, though luckily for him, he did manage to keep a hold of fifth position. A tour later on Lap 22, he finally made it work - leaving him fending off Guenther's Maserati MGS Racing Tipo Folgore but importantly, fifth.
Cassidy's season then did come to a premature end, mathematically out of the fight after retirement from Round 15 - his first of 2022/23.
With nine laps to go Dennis came under attack from fifth-placed Wehrlein into Turn 1. He had it all on keeping the factory Porsche behind him, eventually losing both fifth and sixth to the TAG Heuer Porsche pair when he took a second ATTACK MODE activation.
A big shunt for an airborne Sacha Fenestraz (Nissan) followed just behind Dennis, on Lap 28. The Nissan driver caught the back of Sergio Sette Camara's NIO 333 and hit the wall at Turn 16. It was a hefty impact, but thankfully the French-Argentine walked away unharmed.
Shortly before that Safety Car period a clash between Hughes and Wehrlein at Turn 1 saw the Porsche driver come off worst and into the wall - possibly crucial in the battle for top spot in the Teams' World Championship. The Red Flag was then flown with repairs required to the Tecpro barriers at Turn 16. Third-placed man Rast damaged his McLaren's front wing in the melee, requiring repairs under Parc Ferme conditions, meaning he'd take the restart from the back of the pack - the rest of the order taken as they were.
The Green Flag flew with four laps left to race and Evans led Buemi, da Costa, Dennis, Nato, Bird, Vandoorne, Sette Camara, Mortara, and di Grassi away.
The leader immediately jumped for his second ATTACK MODE activation and held the lead, Buemi followed but slipped to fourth - da Costa and Dennis squeezing by into second and third respectively on Lap 33 - enough to see Dennis home in the Drivers' order.
Nato then fired it up the inside of Buemi in a move for fourth but it was optimistic, to say the least. He caught the Envision and the pair slid into the wall at the penultimate corner - causing a chain reaction behind with cars unable to avoid the melee, enforcing another spell under Red Flag conditions.
It was three lap sprint to the flag at the restart with Dennis in position to take the Drivers' crown with a podium. All he had to do was hold Envision Racing's Buemi behind - though not even that was required in the end as Porsche's da Costa was slapped with a three-minute penalty for a technical infringement.
Evans lead the field home from Dennis and the title was the Brit's - a first British World Champion in Formula E.