China's Peina Chen is virtually certain to earn gold at the RS:X World Windsurfing Championships tomorrow ©RS:X World Windsurfing Championships

China's Piena Chen outshone her rivals on the fifth day of the RS:X World Championships on the Tokyo 2020 course at Enoshima to take an almost unassailable lead into tomorrow's concluding medal race.

Meanwhile in men's racing, the battle for gold lies between China's Bing Ye and Mateo Sanz Lanz of Switzerland, who are tied on 33 points.

The format for tomorrow's racing is a single race of 20 minutes - effectively a sprint around the course - that will be held for the top 10 in the men's and women's fleet, with double points on offer.

Chen, the 2015 world windsurfing champion and 2016 Olympic silver medallist, took advantage of the misfortune suffered by overnight leader Jiahui Wu, who was caught over the start-line in the only women's race possible in failing winds at Sagami Bay today.

The RS:X Windsurfing World Championships are due to finish on the Tokyo 2020 course tomorrow with China having the prospect of gold in both the men's and women's races ©RS:X World Windsurfing Championships
The RS:X Windsurfing World Championships are due to finish on the Tokyo 2020 course tomorrow with China having the prospect of gold in both the men's and women's races ©RS:X World Windsurfing Championships

Chen's victory was her fifth out of the nine races sailed and she now holds a 17.3 point lead over compatriot Hongmei Shi.

Another Chinese windsurfer, third-placed Yunxui Lu, also has a mathematical chance of taking gold but this requires a number of unlikely factors including a last place for Chen.

There are a number of sailors who could stop a Chinese clean sweep of the women’s podium, including Poland’s Zofia Klepacka and Lillian de Geus of The Netherlands, sitting in fifth and sixth overall respectively.

Spain's Blanca Manchon in seventh also has an outside chance of a medal.

Russia's Stefania Elfutina, one of the pre-event favourites, was the last board to get into the top ten qualifying places for medals but she has won the under-21 division with a day to spare after narrowly beating China's Xianting Huang to the medal race.

Two races were possible today in the men's fleet, where Sanz Lanz came out top with a 4.2 scoreline after Ye followed up an uncharacteristic score of 12 in the first race with victory in the second.

Gold will go to whichever of the two joint leaders crosses the finish line first tomorrow, although if the wind does not allow the medal race to be sailed Ye will take the title as he has a better discard.

Pre-event favourite Dorian Van Rijsselberghe, the 2012 and 2016 Olympic champion from The Netherlands, is out of the medals, having only managed to qualify ninth overall for the medal race.

France's Louis Giard, the men's leader over the first two days of racing, is also out of contention, having qualified seventh following a poor final series of results.

The battle for bronze will involve a chasing group including Mengfan Gao of China, Shahar Zubari of Israel and Britain's Kieran Martin Holmes.