Hannah Mills and Eilidh McIntyre held onto the overall lead by just one point after Thursday’s racing.
The British pair (16,4,4) lost out to Ai Kondo and Miho Joshioka (12,5,3) of Japan who clawed their way back into contention, beating the Brits in two of the three penultimate day races.
Going into Friday’s medal race these two teams now have a 15 point lead over third placed Camille Lecointre and Aloïse Retornaz (6,3,1) of France on 63 points.
Elena Berta and Bianca Caruo (2,9,7) of Italy are fourth with 68 points, and Spain’s Silvia mas Depares and Patricia Cantero fifth on 74 points.
Fernanda Oliveira and Ana Barbachan of Brazil were the winners of the first race (R9) of the day, which puts them in the medal race in tenth place and will have helped the nation qualify for Tokyo 2020.
In the men’s championship, Britain’s Luke Patience and Chris Grube managed some heavy lifting on Thursday to qualify for the men’s medal race.
With their best day of the series – a 2, 3 and 6 – they made the medal race cut-off in ninth place with 81 points.
While Spain’s Jordi Xammer and Nicolas Rodriguez (1,1,4) have taken a one point lead ahead of Aussies Matt Belcher and Will Ryan (3,5,1) who are on 24 points in their battle for the title.
Moving into third place are Panagiotis Mantis and Pavlos Kagialis (5,2,3) of Greece tied, on 48 points with Kevin Peponnet and Jeremie Mion of France.
Sweden’s Anton Dahlberg and and Fredrik Bergstrom are now in fifth with 52 points and challenging for the bronze.
470 Women – Medal Race competitors (39 entries)
1st GBR 1 Hannah MILLS and Eilidh MCINTYRE – – 48 pts
2nd JPN 1 Ai KONDO YOSHIDA and Miho YOSHIOKA – – 49 pts
3rd FRA 9 Camille LECOINTRE and Aloïse RETORNAZ – – 64 pts
4th ITA 6 Elena BERTA and Bianca CARUSO – – 68 pts
5th ESP 18 Silvia MAS DEPARES and Patricia CANTERO REINA – – 74 pts
6th SLO 64 Tina MRAK and Veronika MACAROL – – 92 pts
7th POL 11 Agnieszka SKRZYPULEC and Jolanta OGAR – – 97 pts
8th CHN 621 Mengxi WEI and Haiyan GAO – – 100 pts
9th AUS 5 Nia JERWOOD and Monique DEVRIES – – 107 pts
10th BRA 177 Fernanda OLIVEIRA and Ana BARBACHAN – – 109 pts
470 Men – Medal Race competitors (52 entries)
1st ESP 44 Jordi XAMMAR and Nicolas RODRIGUEZ – – 23 pts
2nd AUS 11 Mathew BELCHER and Will RYAN – – 24 pts
3rd GRE 1 Panagiotis MANTIS and Pavlos KAGIALIS – – 48 pts
4th FRA 27 Kevin PEPONNET and Jeremie MION – – 48 pts
5th SWE 349 Anton DAHLBERG and Fredrik BERGSTRÖM – – 52 pts
6th JPN 20 Keiju OKADA and Jumpei HOKAZONO – – 75 pts
7th FRA 79 Hippolyte MACHETTI and Sidoine DANTÈS – – 79 pts
8th ITA 757 Giacomo FERRARI and Giulio CALABRÒ – – 81 pts
9th GBR 4 Luke PATIENCE and Chris GRUBE – – 81 pts
10th NZL 1 Paul SNOW-HANSEN and Daniel WILLCOX – – 92 pts