Both Mercedes drivers made a late pitstop for medium Pirelli tyres as they sought to challenge eventual race winner Carlos Sainz and Lando Norris on their aging hards.
But as Russell sat on the rear of the second-placed McLaren on the 62nd and final lap, Norris clipped the outside wall heading into Turn 10.
The chasing Russell did similar, only he made much heavier contact to damage his W14 and then spear head-first into the barriers.
That dramatic shunt promoted team-mate Lewis Hamilton to third while Russell, who started second and might have challenged for victory, was classified in 16th place.
"In the moment, you just want to curl up in a ball and be with nobody," said Russell. "It is the most horrendous feeling in the world when you are so physically drained, mentally drained.
"We missed out on an opportunity for victory and then to make such a mistake, it is truly heart-breaking."
Despite the major error, Russell reckoned that upon reflection, he was now delivering the best performances of his F1 career.
He continued: "I have to be honest now, and I'm standing here an hour later, it has been such an amazing weekend. I truly believe that I'm driving better than I have ever driven.
"I felt confident and comfortable and I'm not going to let a mistake of two centimetres knock me down. I will have a tough night and a tough morning but I will then just put it behind me and go again.
"I can only apologise to the team because they deserved more but shit happens."
Russell added that his mistake could be put down to a lack of concentration, with the Briton having been knocked out of his groove after realising the win had escaped him.
"It was such a nothing of a mistake," he said. "If I spun off and had a lock-up, it would have been very different but I clipped the wall on the last lap.
"It is such a pathetic mistake and that is why it feels so strange right now.
"It is probably that lack of concentration… It was the last lap and I knew that opportunity was gone.
"It goes to show that you need to stay on it. It doesn't matter what the scenario is."
