The Kiwi entered the Brazilian event having hit the ground running with life at Jaguar, taking a hat-trick of podiums from the opening three races, which included a win in Diriyah that put him 19 points clear in the standings.
But things began to unravel for Cassidy on Saturday as he failed to reach the qualifying duels and was unable to make much progress in the race from ninth, rising as high as fifth but with both Attack Mode activations still to take.
Having damaged his front wing, this ultimately had disastrous consequences as the bodywork became lodged under his car through the fast left-kink of Turn 10, sending him into the barriers.
“I had a few touches [early in the race], my front wing was fine but, unfortunately on that lap, about half a lap earlier, I had a touch and the front wing was quite badly damaged,” he told Autosport. “It was bound to happen at some point I guess.
“It wasn’t really going how I wanted, it wasn’t one of our best races. I’ve got to look internally at myself for that, I’ve got to be better, so I’ll just try and improve.”
Cassidy was visibly unhappy having missed out on progressing through his qualifying group by just 0.011 seconds, while team-mate Mitch Evans was able to fight Sam Bird for the win after starting fourth.
“I was second in FP1, in FP2 I was the quickest car on 300kw and quickest car outside of qualifying,” he said.
“I don’t believe qualifying was my error but the race I could have done a better job.
“I can’t comment too much on it [qualifying], but for the race I need to do a better job.”
When pressed on whether it was a team error that had cost him a shot of progressing in qualifying, he said: “That’s racing, there’s no one to blame we just need to do a better job.”
Despite failing to score any points in Brazil, Cassidy still leads the standings, albeit by only four points from Porsche’s Pascal Wehrlein, as just 20 points cover the top six drivers.
“I think I was one of the fastest cars this weekend,” added Cassidy.
“I’m still leading the world championship, I’ve come off three podiums in a row, I have no reason not to be confident going into Tokyo.”