Chen and Quan had led throughout yesterday's preliminary round and semi-final, and had been expected to battle closely for gold in the final.

After five dives each, there were only 0.30 points to divide the pair, but it was Tokyo 2020 silver medallist Chen who did just enough to make it back-to-back World Championship golds in this event.

Quan had led the first two rounds with a forward 3.5 somersaults pike and inward 2.5 somersaults tuck which scored 85.50 and 91.20, respectively.

However, the tide turned when Quan delivered a disappointing back 3.5 summersaults tuck in the third round, which merited only 61.05.

Chen's armstand back three somersaults earned her 85.00 in the third round, putting her on 258.00 points to Quan's 237.75.

Quan recovered with a 91.20 armstand back two somersaults with 1.5 twists free, but trailed by 9.90 going into the final round after an 80.85 from Chen's back 3.5 somersaults tuck.

The Olympic champion piled serious pressure on her compatriot with a back 2.5 somersaults with 1.5 twists pike, helping her to finish on 416.95.

Chen's final dive was her lowest-scoring of the final, but 78.40 from the same routine meant she held onto first place with her total of 417.25.

Pandelela Pamg of Malaysia prevailed quite comfortably in the battle for bronze, scoring 338.85 to stave off challenges from Brazil's Ingrid Oliveira and Canada's Caeli McKay, who notched 327.10 and 318.45, respectively.

Men's and women's open water swimming medals were also decided at Lupa Beach in the 5 kilometres race.

Germany's Florian Wellbrock triumphed in the men's race, clocking 52min 48.80sec, with Italy's Gregorio Paltrinieri 3.90sec further back in second.

Mykhailo Romanchuk of Ukraine completed the podium in 53:13.90.

The gold was Wellbrock's fourth medal of the World Championships, following his men's 800m and 1,500m freestyle swimming silver and bronze and Germany's success in the mixed 4x1,500m open water swimming relay yesterday.

The women's 5km race was settled by an even finer margin, Ana Marcela Cunha triumphing by 0.90 to defend her title and consign France's Aurélie Muller to silver for the third consecutive World Championships.

Cunha raced to victory in 57:52.90, followed by Muller with 57:53.80.

Giulia Gabbrielleschi of Italy came through in third in 57:54.90.

Wellbrock and Cunha were both Olympic gold medallists in the 10km races at Tokyo 2020.

There is no open water swimming tomorrow on the 11^th day of the FINA World Championships, but diving finals are scheduled in the men's 3m springboard and men's 10m synchronised.