Russell lost 18 points to Kimi Antonelli, with the gap now at 84.
The Mercedes driver suffered his third retirement of the season in Malaysia, and a second where the power unit was to blame.
Having clawed back some of the margin to his championship-leading teammate Antonelli last time out in Baku, the gains were instantly swept away.
At the time, Russell had been lapping in third place, one position behind Antonelli and looking likely to only lose three points on his rival.
“You’ve almost got to laugh,” Russell told Sky Sports.
“I’m beyond disappointment. It’s just so many times this season it’s happened.
“It’s a real shame. Of course, it’s a real shame, but just keep on fighting, just keep on trying to go.
“The podium, of course, looked very certain. Solid race, not amazing race, but a solid race. But yeah, not the first time, so I’m pretty used to this feeling and these questions, let’s say.”
Russell’s Mercedes crawled to a halt moments before an expected safety car restart.
Pulling off on the run to Turn 1, the failure bore an eerie resemblance to a failure that struck Lewis Hamilton in 2016, which put then-Mercedes teammate Nico Rosberg into pole position to take the title.
As the championship enters its final throes, Russell refused to state out loud that the title battle is over.
“I don’t need to say I think it’s gone or whatever, but of course it’s exceptionally likely, and that’s just the reality,” he added.
“I knew if I wanted to come back, I needed luck on my side. Unfortunately, I’ve had luck not on my side.
“A three-point loss today, being behind Kimi, turned into an 18-point loss, and of course, if the issue had been on the other side, it would have been an 18-point gain. So it’s a real shame, but that’s just how it is.”
Antonelli has already taken a back-of-the-grid penalty for an engine change this year – at Monza, when he stormed through to victory – and Russell was already expected to take this hit in the coming races.
It is unclear at present how this latest problem will affect these plans, with further parts potentially required to complete the season.
