Lewis Hamilton is in a race against time as he battles to recover from Covid-19 and return to action for Mercedes at the season-ending Abu Dhabi Grand Prix, according to team chief Toto Wolff.

The Austrian boss told reporters after Sunday's dramatic Sakhir Grand Prix, in which the seven-time champion's substitute George Russell excelled, that Hamilton's condition was improving every day.

But, he added, he had to complete a full recovery and return a negative coronavirus test result by Thursday – and, if not, super-sub Russell, on loan from Williams, would take his seat again.

-If Lewis recovers - and he is getting better every day - and he is being considered Covid-free and negative then he will be fine- said Wolff. -I think we need to see how well Lewis recovers.-

-That's the most important - that he's well - and he says he's a bit better so he's made a big step.

-If the test is negative, it's his car and then, I am sure, he will drive a brilliant race. But, if the test in Abu Dhabi is positive, then George is in the car.-

Wolff rejected suggestions that the prodigious Russell's dazzling display for Mercedes –- he looked certain to win the race until a pit-stop bungle and a puncture ended his challenge -– was a useful factor in negotiating a new contract with Hamilton.

-No, they are two different things- he countered. -Lewis has been with the team for eight years. We have had great success in the past. -

-He is a team member and I have said it already - none of the events will interfere or change any of our negotiations. That wouldn't be fair against him and it wouldn't be fair against us. -

-It could have gone the other way around and been a race weekend where George wouldn't have been on the pace. Our negotiations go much beyond that.-

Hamilton will be out of contract at the end of this season. Talks, postponed due to his illness, are expected to resume later this month.