Jaguar came to Formula E's London finale with a 1-2 in the drivers' championship, but a bruising day means it now trails Porsche’s Pascal Wehrlein before the final race.

Yes, Jaguar is still on course for a first teams' championship (a 36-point gap should be enough), but it risks letting the all-important drivers' crown slip away.

Nick Cassidy had a 12-point lead in the championship prior to London but this was soon obliterated by a miserable qualifying, an incident-filled race and some inch-perfect decision-making from Porsche.

So what went so wrong for Cassidy and why was team-mate Mitch Evans - nine points adrift before the race - unable to stop Wehrlein being the one to reap the rewards? 

Genesis of Cassidy’s misery

Have a few drops of light British summer rain been more damaging than they were in London Docklands on Saturday afternoon?

The only precipitation seen at the exhibition hall venue all week fell just before the first qualifying group, with points leader Cassidy in it.

The Jaguar driver had been on a high after a strong free practice two session in the morning when he was by far the fastest 300kW lap achiever.

He knew he had a good car underneath him and that a crack at the front row at least was on. That all fell apart when he overheated his Hankooks by doing a double push. It was then the spiral of his day really began to play out.

“Basically, the track was getting better and better, we were quite aggressive on the rear tyre and when the track was great at the end of the session it was way, way, way out of the window,” said Cassidy with a qualifying disaster that left him 17th on the grid. 

“I just couldn’t believe, in a way, how it played out - that for our session we get one bit of rain that changes [everything].

“We were quickest on merit, on pace [in FP2]. I really didn’t need a crazy session.”

Dennis the Menace infuriates Cassidy

Starting down in 17th, Cassidy was right in the rough and tumble. And an attack mode-activated Jake Dennis, a driver who was on the receiving end of some tactical contact shenanigans via Porsche stablemate Wehrlein last year, seemed intent on dishing some out himself.

Dennis's aggressive wheel-banging manoeuvre prompted the first bit of Cassidy's fury to crackle the airwaves of his radio.

“What the f*** was that by Dennis man?” he ranted. “He just shoved right into me. He crashed right into me. My steering is all bent.”

Dennis was issued with a 10-second penalty for that, in addition to the five seconds he received for a lap one incident with Robin Frijns, a shunt that left the Envision Racing driver heading to hospital for checks on his wrist. A five-second penalty for colliding with Jean-Eric Vergne (something Vergne told The Race was a "racing incident") took Dennis's total to 20 seconds, something that was no comfort to Cassidy. 

Cassidy had questioned 'how much does Porsche pay him?' over the radio and urged the stewards to penalise him by "send[ing] him through the f***ing pits" as his battle with Dennis went on.

Speaking to The Race after the contact, Cassidy said of Dennis that he had “a lot of respect for him, he’s a fantastic driver.

“We obviously went toe-to-toe in the world championship last year, he came out on top, I’m not going to take that away from him at all. But today he clearly had a job to do I guess.”

But it wasn’t just the irritation of the contact that riled Cassidy so. It appeared to have a practical legacy too, one that affected him taking the all-important attack mode power boost - something he needed four attempts to do successfully the first time around.

“He hit me wheel-to-wheel, I think that was on TV, but there was another one where he turned hard right onto me when we were heading down the hill into T6, and I just don’t know if that moved my underfloor, to the transponder," he said. 

“It was not right and I missed attack mode three times in the race and each time I missed it that was a two-position loss.

“Gaining one position in London is hard so a total of six to come back from certainly didn’t make it easy and there’s almost no strategy then, so it felt like I was going back to last every time."

From Dennis’ viewpoint, the contact was “like a feather's touch, extremely harsh” and “absolutely ridiculous”.

But that incident wasn’t the end of the Andretti driver’s disruption, in Cassidy’s mind.

Needing every point he could muster in addition to the six he salvaged, Cassidy was intent on going hell for leather to grab the precious fastest lap. But ahead of him was that familiar red, white and blue Andretti Porsche of the outgoing champion who slowed the pack and eroded any chance of Cassidy being able to grasp the bonus point.

“Right until the chequered flag there was a determination to make my life difficult,” rued Cassidy.

“I don’t want today’s race to change my judgement or respect for him, I think he’s world-class, but certainly it was very difficult circumstances for me to race in.”

But Dennis was adamant that the perceived spoiling tactic had “nothing to do with that” and was more designed to “hold up Sacha [Fenestraz] so he didn't get points.

“We're fighting with him [Nissan] in the constructors' (for third position). I had no idea Nick was in the race. No idea where he was.”

It's no surprise that after such a bruising set of incidents, Cassidy felt "relieved" to still walk away with six points.

Evans and Buemi compromised each other

With Cassidy out of the picture in terms of scoring big points, why couldn't Jaguar's other driver take full advantage?

That's partly because Jaguar got far from everything right on Saturday when it came to the management of Evans's race, and ironically a good slice of that involved Sebastien Buemi’s customer Envision-run Jaguar I-Type 6.

Evans and Buemi started from the front row and ran first and second each in the early stages when each tried to stay in the lead but probably for too long.

“I think that was the wrong approach,” Evans told The Race.

“We needed to get into the tow and that would have changed things a lot. Pascal was just accumulating so much energy behind us and Seb had the same idea, he wanted to be in the lead."

Buemi was finding it difficult to under-consume at the right amount to get his target up and ultimately both he and Evans simply hurt each other from an energy perspective by staying in the lead for too long.

When Wehrlein left his attack mode strategy deliberately late and crunch time came around these attacks, the Porsche 99X Electric’s energy advantage was enough that Evans couldn’t defend.

Once Wehrlein went by the Jaguar he was able to get his attack modes done and use the extra power with a higher target. Evans already knew at this stage that it was all over.

“I burnt a lot trying to get track position after his attack, when he went for the second activation, just to try and get track position and hope for the safety car but I couldn’t quite get it done and then my target dropped a lot and I was a sitting duck," Evans explained.

It's no surprise that Evans was left “surprised and obviously disappointed” by the outcome of a race he probably should have been able to win.

Why didn't Jaguar’s customer help it? 

With a whopping points discrepancy of 234 between leader Jaguar and seventh-placed customer team Envision ahead of Saturday, there was a clear gaping void in what was at stake for each.

Jaguar, with a 33-point gap over Porsche, was in a very favourable position in the teams’ standings, and in reality, still is after Antonio Felix da Costa’s Oliver Rowland-triggered incident at the final corner.

It therefore seemed logical for Buemi to be deployed for a disruptive assistance plan for Evans in the race.

While Buemi’s engineer Connor Summerville did relay some Evans-friendly messages to his driver (“our race is covering Wehrlein”) early doors, it simply didn’t play out well enough from Evans and Jaguar’s point of view.

Evans, when asked by The Race if he expected the extended Jaguar family of Envision was helping, replied: “Are we [a family with Envision]? 

“It doesn’t feel like it. I don’t know if there were discussions but the feeling I get is they’ve made it very clear they’re not going to help.

“I wasn’t expecting any help. I think it was made quite clear there wouldn’t be any support [from Envision], like Andretti and Porsche."

Those opinions were backed up to a large extent by Buemi himself, who said that looking out for Evans and Jaguar wasn’t the overriding concern.

“I don't want to do anything silly, but my objective was to win the race,” he said.

“I wanted to do a good job, I wanted to score big points. To some extent, I didn't really care what was happening with them [Jaguar]. I was doing my race as strongly as I could.”

The relationship between Jaguar and Envision felt strong and close last season, more so than it does this. Envision’s teams’ title success was lauded by Jaguar last year but clearly, like with Andretti and Porsche too, a redressing of some balance has taken place since.

Will that thaw and heal a little from Saturday to Sunday as the title fight ratchets up from important to critical?

“Probably not, but that’s a conversation for [team bosses] Sylvain [Filippi] and James [Barclay] to have,” surmised Evans.

“But I’m definitely not expecting it. It would be nice, if it came to it, but let’s see.”

Wehrlein's risk/reward brilliance

Evans got the risk-taking right in qualifying but it was Wehrlein and Porsche who judged things to perfection in the race. 

The only hint of chaos in Wehrlein's race was the crunching of carbon fibre he could hear behind him.

He didn't let dropping behind Norman Nato at the start of the race take him off course, and he and the team then played the energy game to perfection when Buemi and Evans became fixated on each other.

Wehrlein came storming through the middle and a well-judged overtake and later squeeze on Evans were exactly on the right side of the risk/reward balance that you need to win a title.

Wehrlein has gone missing at times this year, most notably when his team-mate da Costa romped to four victories in five races while Wehrlein managed one podium in the same period, but he was faultless on Saturday evening.

And it puts him in prime position for Sunday with a simple goal: finish ahead of both Jaguars and achieve a highly emotional title.

"It feels like home for me. I grew up one hour away from the Porsche factory," Wehrlein told The Race.

"I spend a lot of time with the guys, I enjoy being with them. You can hear that, I can definitely feel that. 

"I also really want to win for the team because I believe they deserve it and I probably would be more happy for them than I would be for me."