Roberto Martinez has revealed that Belgium are sweating on the fitness of three star men ahead of their World Cup showdown with England.

The Red Devils are in pole position at the top of Group G after adding a 5-2 rout of Tunisia on Saturday afternoon to their 3-0 win against Panama.

Belgium looked impressive in an attacking sense at the Spartak Stadium, with Eden Hazard and Romelu Lukaku helping themselves to a couple of goals apiece, while substitute Michy Batshuayi also registered late on.

Ahead of next Thursday's likely top-spot shootout with England in Kaliningrad, however, Martinez has confirmed that Hazard, Lukaku and fellow forward Dries Mertens - each substituted against Tunisia - are all carrying knocks that could rule them out.

Martinez told reporters after the match that Lukaku has "external ligament" damage in his left foot, Hazard has a problem with his calf and Mertens suffered "a bit of a knock on his ankle".

Belgium will assess the fitness of all three players within the next 48 hours.