The duo won the World Championship title at the start of August and followed up with victory in the Ready Steady Tokyo test event on the Olympic course at Enoshima Yacht Harbour last week.

They face a three-way battle at the top of the standings, with Spanish and Swedish fleets hot on their heels in Japan.

With gusts exceeding 25 knots, Belcher and Ryan recorded a pair of second places to top the rankings on nine points.

Jordi Xammar and Nico Rodriguez of Spain finished fourth and first in the opening races to place second overall on 23 points, with Sweden's Anton Dahlberg and Fredrik Bergström in third on 27 points.

"Both teams have always been up there to be honest," said Belcher of their rivals for gold. 

"We've had some really close battles in the past, notably with the Swedish a couple of years ago at the World and European Championships.

"They are extremely talented and always in the mix. 

"The same for Jordi and Nico – they’ve really picked it up recently in strong breeze, but might have gone down a bit in lighter wind."

Three further races will be held tomorrow before the medal race on Sunday (September 1).

In the women's 470 fleet, Italians Elena Berta and Bianca Caruso overhauled Nia Jerwood and Monique De Vries at the top of the leaderboard.

They secured first- and fifth-place finishes to move one point clear of their Australian rivals, with Spaniards Silvia Mas and Patricia Cantero in third place.

Berta and Caruso have a total of 22 points, with Jerwood and De Vries second on 23 points.

Mas and Cantero sit in the bronze-medal position on 29 points, one point ahead of Italian duo Benedetta di Salle and Alessandra Dubbini, who carded first and second places to move up the rankings.

Just one race was completed in the 49er fleet as strong winds forced the second race to be abandoned as sailors capsized.

Austrian pair Benjamin Bildstein and David Hussl's victory moved them up to third in the standings.

Tim Fischer and Fabian Graf of Germany are in pole position despite finishing ninth.

They are seven points clear of Poland's Dominik Buksak and Szymon Wierzbicki ahead of tomorrow's medal races.

The Nacra 17 and 49erFX races were postponed, meaning the top 10 sailors advance to the medal races tomorrow.

Annemiek Bekkering and Annette Duetz of The Netherlands lead the 49erFX standings, with Britain's Ben Saxton and Nicola Boniface top of the standings in the Nacra 17

The 49er, 49erFX, Nacra 17 and RS:X fleets will conclude racing on Saturday 31 August with their medal races.