Romelu Lukaku is out of Belgium's opening Euro 2020 qualifier due to a foot injury, coach Roberto Martinez has confirmed.

Lukaku missed Manchester United's last match, an FA Cup quarterfinal defeat away to Wolves, because of the injury.

And the striker has not recovered in time to lead the line for Belgium as it opens Group I against Russia on Thursday.

Martinez, however, suggested Lukaku may be ready for Belgium's second qualifier, against Cyprus, on Sunday.

"The relationship with Manchester United is very close," Martinez told reporters. "The only thing that matters is Romelu is fully fit.

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"We want him fit but it has to be in the right way. We've been happy with his progress but at the minute he is still unavailable."

Lukaku has scored 12 Premier League goals this season and hit a brace three games running for United recently, but questions have been asked about his form.

"He is a player that has not been discovered overnight. He has been scoring goals since [the age of] 16," Martinez added.

"He is already the top goalscorer in the history of Belgium football. Goalscorers will go through good and bad spells but he made history in Belgium football.

"He has to be fully fit though, like any other player. We wouldn't take a risk with any player on the pitch."

As well as Lukaku, Belgium will be without Borussia Dortmund midfielder Axel Witsel, as well as Manchester City duo Kevin De Bruyne and Vincent Kompany.

"Russia are an experienced team and they handle the pressure very well and they deserve respect after their great World Cup," said Martinez.

"The Russians do not need to have a lot of the ball to hurt, they are able to be quickly in the opposing box.

"Despite the absences, I'm happy with the options I have. I think it's better to talk about the players in the selection rather than the absent ones."