Leg 8 set off on Sunday as if the fleet were wading through treacle on a glorious but stiflingly humid Lisbon afternoon, which deprived the fleet of power with only the lightest of winds.

The crews will not be able to enjoy such a tranquil ride for long. The leg is only 647 nautical miles (nm), and much the shortest so far, but the forecast is for plenty of breeze to kick in, especially around the Bay of Biscay.

In-form MAPFRE made the early pace as the fleet attempted to deal with the tough, near windless conditions, as well as the iconic iron bridge which straddles the tidal Tagus River.

Abu Dhabi Ocean Racing was struggling at the back of the pack in sixth place early on, but it was still very early, even on such a short stage and sure enough as the breeze filled in they worked their way through the fleet.

Team Brunel had the honour of leading the fleet past the final gate with Team Alvimedica and MAPFRE hot on their heels.

A nearly wholly upwind leg is now expected and a test of sailing technique that the fleet has yet to face in more than eight months of racing.

Ian Walker, skipper of Abu Dhabi Ocean Racing, for one, is anticipating the challenge with relish since the fleet has yet to be tested in this kind of condition – a voyage, in some ways, into the unknown.

“There are light winds chasing up the Portuguese coast, but by the time we get to Cape Finisterre, it should be a dead beat to Lorient, and probably quite windy, over 30 knots,” he says.

He is banking on plenty of upwind sailing. “It’ll be interesting as we haven’t had a lot of upwind in this race. We don’t really know what the pecking order is in these conditions, so it could be a very different leg to the others.”

The race is intriguingly poised with Abu Dhabi Ocean Racing, on paper, able to clinch overall victory if results go their way when the boats arrive after three to four days of sailing.

Should they win, and their closest rivals, Team Brunel and Dongfeng Race Team finish fourth or worse, then Ian can loft the trophy in France.

However, he brushed aside all premature talk of that prospect at the pre-leg press conference on Friday.

“There’s a lot of this race left. In offshore sailing, you can lose it going up a river at the end,” he said.

“I’ve seen Admiral’s Cups lost in the dying seconds. We’re a long, long way from winning this race. When you start to think you’ve got it won, that’s when you start to lose.”

“I prefer not to even look at the scoreboard – these guys (his rival skippers) know they still have plenty of chance to beat us in this race.”

It is not just Team Brunel and Dongfeng Race Team who will want to upset Walker’s bid to claim the trophy prematurely in Lorient.

MAPFRE are currently in red-hot form.

They were narrowly pipped by Team Brunel into Lisbon at the end of Leg 7, but bounced back with a paper-thin, in-port race victory here on Saturday at the expense of Walker’s Emirati boat.

Their cause is boosted by a desire to underline their credentials as one of the classiest crews in the fleet, after two separate brushes with the independent, international jury following rule breaches cost them a total of three points.

Similarly, Team Alvimedica are improving leg on leg, and have garnered two podium places in the last 10 days: third in Leg 7 and the same position in the in-port race.

They spent much of their pre-race build-up based in Lisbon, training in Tagus River and nearby Cascais and were hoping to make that local know-how pay in the early stages of the leg.

Team Vestas Wind are simply delighted to be back in the mix again, after climbing their own Everest simply to repair their shattered boat in time to re-join the fleet for the final two legs.

Team SCA know that the last two, sprint, coastal legs – the ‘European Tour’ – offer them their best chance of upsetting the established order of dominance.

They too have improved leg after leg, but that progress has yet to be rewarded on the scoreboard. Skipper Sam Davies, whose home is near Lorient, would love nothing better than to claim their best results at the climax of the 12th edition.

“It’s a shorter leg, a sprint, which is a little bit different. We know that we can stay with the group – we’ve been in the lead after three or four days in other legs,” she said in a pre-leg interview.

“We have a good chance. These last two legs are the ones that stay in everyone’s memory at the end of the race.”

The fleet is expected to reach Lorient early on Thursday (June 11).

They will have a short maintenance period there before setting off for the final leg to Gothenburg on Tuesday, June 16 and the event finishes with an in-port race in Gothenburg on June 27.