Fifteen-year-old Ren, the first Chinese Olympic champion to be born after 2000, achieved the highest-scored dive of the evening at 94.05 points, which gave her a total of 439.25 points.
Her teammate, 17-year-old Si Yajie, took second place with a score of 419.40 while Canada's Meaghan Benfeito won the bronze with 389.20 points.
Bearing a serious expression throughout her five dives, Ren only broke out into a small smile after her final score was tallied. "I wasn't very nervous today, I was just focused on my routine," she said.
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"My coach told me to take one dive at a time, to think through my routine before I embark on each dive," said Ren, who also took the gold in February's FINA Diving World Cup in Rio, the last big international competition before the Olympics.
Just 19.85 points separated Ren from 17-year-old Si, who had tied with her teammate on the first dive but later faltered slightly behind on her subsequent attempts. Si had taken the top spot in the semi-finals and preliminaries.
"My goal was the gold medal, it's a pity I didn't win it," she said.
With the men's individual 10m platform event still to go, China has so far claimed six out of the eight diving golds available.
"(The Chinese) stay the best in the sport and that's why they're always one and two," said Benfeito.
"They're just great at diving, they train so hard, not that we don't train as hard as them, but they're just born to dive."
The bronze is the first individual medal for Benfeito, who has two synchronized bronze medals from London and Rio.
"I decided not to look at the scoreboard this time, so I didn't know where I was until the last dive....I was hearing the cheering and I knew it was loud, I knew it was a good event."
"If I were to finish with that score and I finished fourth, fifth, sixth I would have been really pleased. Knowing that I gave my everything, just winning a medal just makes it even better, she said.
Jessica Parratto of the United States, who placed second in the semi-finals, in between Si and Ren, was in medal-winning position after two rounds, but mis-timed her entry into the water that gave her only 44.80 points, the lowest-scoring dive of the competition.
"I got into the final, that was huge for me," she said. "Obviously I didn't do as well as the prelims or the semis but, splitting up the Chinese, that meant a lot to me."
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