Barcelona - He Zi's winning margin of 0.10 points was the smallest ever in diving in world championships history on Tuesday as China raked in its fourth and fifth gold medals in six events.
He Zi won the women's 1m springboard before Qin Kai and He Chong topped the men's 3m synchronized springboard.
He Zi edged Italy's Tania Cagnotto by executing a flawless final dive to win her second world title in the event.
She totaled 307.10 to Cagnotto's 370 points to reclaim the title she first won in 2007.
"I'm a little surprised by the result of the day," He Zi said. "But I am very happy. I haven't thought about (the margin of victory).
"I can't even believe that I have the gold medal."
He Zi has won four career world medals in various diving events.
She also took gold at the 2012 Olympics in 3m synchronized springboard and silver in the 3m individual springboard.
Cagnotto collected her second silver at these worlds after finishing second with Francesca Dallape in the women's 3m synchronized springboard on Saturday.
Wang Han of China took bronze with 297.75, adding to her silver in 2011 and bronze in 2009 at this event.
"I wish diving wouldn't be that close because it hurts," Cagnotto said.
"Of course I am a little disappointed because I don't know if I will have more chances like this to win a world championship.
"But if I think about my year and how I really took it easy and didn't come here in shape, it's OK."
He Zi started well at the Montjuic pool with its views of the Catalan capital by performing an inward pike with 1 1/2 somersaults to lead by more than three points from Cagnotto and Wang.
However, a resurgent Cagnotto entered the final round with a five-point lead over He Zi.
She looked set to win her first world title after a reverse pike with 1 1/2 somersaults drew wild cheers from the smattering of Italian fans.
But on the last dive, He Zi nailed a difficult reverse with 1 1/2 somersaults and 1 1/2 twists for 66.30 points, the highest single score of the final.
Cagnotto said she had had to deal with bigger blows than this.
"I already had this kind of experience in London, but it was worse because I was 0.20 behind the bronze," she said.
"(Today) I'm happy and satisfied.
"This is the first time I got so close to the Chinese, and it is an honor to be so close to them."
Qin and He Chong showed they were far above the rest of the men's field by never trailing and almost deciding the title halfway through the final by hitting a tough forward pike with two-and-a-half somersaults and two twists for 87.72 points.
In the men's 3m synchronized final, Qin, who was diving with He Chong for the first time at a major competition, recorded his fourth-consecutive world title in the event.
He Chong added the gold to his two world titles in the 3m individual springboard from 2009 and 2011 and his Olympic gold medal in the individual event from 2008.
Qin and He Chong ended up with an unassailable score of 448.86 points, giving China its seventh gold in the men's 3m synchronized springboard in eight editions of the world championships.
Russia's Evgeny Kuznetsov and Ilia Zakharov repeated their silver medal from 2011 with 428.01 points, and Mexico's Jahir Ocampo and Rommel Pacheco took bronze with 422.79.
Results in the world swimming and diving championships on Tuesday:
10km Open water swimming:
1. Poliana Cintra Okimoto (BRA) 1hr 58min 19.2sec, 2. Ana Marcela Cunha (BRA) 1:58:19.5, 3. Angela Maurer (GER) 1:58:20.2, 4. Kalliopi Araouzou (GRE) 1:58:21.3, 5. Anna Olasz (HUN) 1:58:22.4, 6. Ophelie Aspord (FRA) 1:58:23.2, 7. Fang Yanqiao (CHN) 1:58:23.2, 8. Rebecca Mann (USA) 1:58:23.4, 9. Eva Risztov (HUN) 1:58:23.4, 10. Christine Jenkings (USA) 1:58:23.6
1m springboard diving:
1. He Zi (CHN) 307.10 pts, 2. Tania Cagnotto (ITA) 307.00, 3. Wang Han (CHN) 297.75
3m synchronised springboard diving:
1. Qin Kai/He Chng (CHN) 448.86 pts, 2. Evgeny Kuznetsov/Ilia Zakharov (RUS) 428.01, 3. Jahir Ocampo/Rommel Pacheco (MEX) 422.79