Belgium boss Roberto Martinez claims Romelu Lukaku is not interested in claiming the World Cup Golden Boot but, on this evidence, he may not have a choice.

Lukaku scored twice in the 5-2 rout of Tunisia in Moscow and produced a magnificent all-round centre-forward display. Following his opening-match brace against Panama, he now has four for the tournament and is level with Cristiano Ronaldo as leading goalscorer.

The theory behind Martinez's point was that Lukaku was more interested in helping the team rather than focusing on individual honours.

"He will tell you, he's not here to be the top scorer at the World Cup," said Martinez. "He's here to help the team to win and do his role. His role is of someone who can score goals."

It's the kind of throwaway line often used by a coach: the team comes first. And it makes perfect sense.

Speaking in his pre-match news conference, Martinez also said Lukaku was benefiting from being asked to contribute less in other facets of the game: dropping deep, linking up, being the focal point.

That, according to the Spaniard, had cleared Lukaku's mind and enabled him to focus on his primary task of scoring goals.

It is, therefore, hard to know what Martinez would have made of the burly number nine's performance at Spartak Stadium for every responsibility he was supposed to have relinquished he displayed in spades.

Just 13 minutes had elapsed when Lukaku escaped down the right and whipped in a perfect cross that Eden Hazard, who had already scored having won and converted a penalty, uncharacteristically fluffed.

Three minutes later and Lukaku had his first goal of the afternoon, peeling off his marker and placing an inch-perfect, left-footed shot into the bottom-right corner.

At that point, Belgium were flying and it seemed only a matter of how many they would get.

But, not for the first time at this tournament, a highly fancied team failed to kick on and Tunisia responded immediately through Dylan Bronn's glancing header.

Martinez's men were wobbling with the only constant being the excellence of Lukaku.

He could have made it 3-1 after 26 minutes but having again found space was unable to convert after trying to round Tunisia goalkeeper Farouk Ben Mustapha.

A precise heeled lay-off to Axel Witsel saw the midfielder lash over, before Kevin De Bruyne failed to find the right pass after Lukaku played him into space on the edge of the box.

Tunisia were bossing midfield but still looked fragile defensively and after coughing up possession once again, Thomas Meunier played in Lukaku in first-half stoppage-time and, with his right foot this time, he chipped delightfully over the advancing Ben Mustapha.

The goal made Lukaku the first player to score at least twice in consecutive World Cup games since Diego Maradona did so against England and Belgium in 1986. Lofty company.

Having watched Hazard grab his second to make it 4-1, Lukaku was withdrawn after 59 minutes. Not De Bruyne, not Dries Mertens, not even Hazard. Martinez was preserving his main man for the challenges to come, starting with England on Thursday.

Lively substitute Michy Batshuayi added gloss with a late fifth, but, despite the emphatic scoreline, this was far from the perfect Red Devils performance, emphasised by Wahbi Khazri grabbing Tunisia's second deep into stoppage time, and there remains plenty for Martinez to work on.

In Lukaku, however, they have a man in form and to be feared.

"I think Rom now knows his role," added Martinez on Friday. "I wouldn't expect any player to work towards an individual reward, the players know what they have to do to make a winning team."

That may be so Roberto, but don't be surprised to see Lukaku scoop the individual reward he doesn't crave.