The 18-year-old had bombed on Friday in a nervy short programme that left him languishing in 17th place going into the decisive day.
But Chen could yet grab a medal after a remarkable free skate that earned him 215.08 points, one of the highest scores ever seen in the sport.
Chen did it on the back of six quads -- four rotations in the air -- breaking his own record of five set last year.
"I have been working on it for a while. It's never really fully come together," Chen said.
"I was like, 'I already fell so many times (in this week), I might as well go out and throw everything down and see what happens."