Lewis Hamilton and Mercedes motorsport boss Toto Wolff admit they are uncertain if the pace problems suffered at the last two Grands Prix will be overcome this weekend in Japan.

Despite claiming victory in Singapore and pole last weekend in Malaysia, the Anglo-German team was arguably the third fastest of the top three, with the change in weather helping them on race day at Marina Bay and Ferrari's own reliability issues saving them at Sepang.

Though the high temperatures at both races would play to a weakness of Mercedes in recent years, the large deficit they were facing, particularly last weekend on a circuit that should have suited them has raised the prospect of whether the three-time defending champions have now simply been caught.

“In the last years, we have performed very strongly there (at Suzuka), but recent weeks have reminded us that historic form counts for little with these 2017 cars and tyres," Wolff commented earlier in the week.

“It is a circuit which rewards Grand Prix cars and drivers performing at their very best - and we expect a very close fight between ourselves, Ferrari and Red Bull.

“After Malaysia, we have found ourselves doing analysing our problems, beginning to understand their causes and working on solutions,” the Austrian added, “However, this is not the work of a moment.”

Amid the search for answers, Hamilton now faces a dilemma of what to do this weekend at Suzuka after the decisions he made last weekend. Following the difficult practice, he would discard upgrades brought to Sepang in favour of the setup used in Singapore.

Though in theory slower, the Briton would be much faster than teammate Valtteri Bottas who remained with the new parts in qualifying and the race yet he admits it will need team co-operation to decide the best path in Japan.

“It’s not decided at the moment,” he said. “It’s a constant discussion from the guys. I think the guys want to go one direction and I’m hesitant and more feeling for another way.

“I’ve got a huge amount of trust and belief in the team and know they want to win as much as me, so collectively we will come to an agreement on what we do and make sure we make the right decision.”

What may hamper making that decision is the weather as rain is forecast all day on Friday and early Saturday, meaning all three practice sessions could be of little use with a dry race expected.

Should the prediction prove accurate, Hamilton conceded: "That will make it difficult for us to feel straightaway whatever setup we do have.”