Belgium's forward Eden Hazard celebrates his second goal during the Russia 2018 World Cup Group G football match between Belgium and Tunisia at the Spartak Stadium in Moscow on June 23, 2018 Image Credit: AFP

Moscow: The World Cup has yet to see the best of Belgium, striker Romelu Lukaku warned on Saturday after scoring twice in the Group G seeds’ 5-2 demolition of Tunisia to all but secure qualification to the next round with a game to spare.

Thursday’s clash in Kaliningrad against England, who can assure their own qualification by beating Panama on Sunday, will stretch a side that truly believes it can go all the way in Russia and better a previous best semi-final finish.

“We can still do better,” said the Manchester United forward, whose four goals in two games beat a previous Belgian record for scoring in a single World Cup finals and matches the current tournament leading scorer, Portugal’s Cristiano Ronaldo.

“It is important we did better than in the previous match. That is what we did,” he added. “Against England we still have to do better.” Already by far Belgium’s top scorer in all international competitions with 40, at just 25 Lukaku is carrying high hopes that he is the final piece in a jigsaw — providing the clinical finish that intricate build-up play from the likes of Eden Hazard and Kevin De Bruyne has provided in recent years.

“Today all the offensive players were able to bring something and the defenders were there too. As a team we keep improving,” he said, playing down his own prospects of claiming World Cup records.

Replaced on the hour after nursing a bang to his heel, Lukaku said the injury did not seem too serious: “I could have gone off right away but I wanted to push it. We’ll see with the physio tomorrow.”

For coach Roberto Martinez, a couple of goals for Hazard and one for stand-by striker Michy Batshuayi mean a knock for Lukaku should not be too worrying. Under the Spaniard, Belgium’s “golden generation” are finally coming together after two disappointing quarter-final exits at the last World Cup and Euro 2016.

“It’s not easy to score the amount of goals we did in two games,” he said, recalling an opening 3-0 defeat of Panama.

Belgium have never scored five in a World Cup game before.

“It’s really good to see a team coming together and wanting to fight so much for each other and then on top you’ve got the talent and the quality,” added Martinez.

“It’s been a joy since the day we came together to see a group of players working so hard for each other.

“We were in full flow going forward, we looked really sharp.”

Belgium were much the better team from the off, looking dangerous on almost every attack, but they were seriously aided and abetted by some ragged defending and non-existing marking from their opponents.

Syam Ben Youssef needlessly crashed into Hazard to give away a sixth-minute penalty, which the captain calmly converted.

Ali Maaloul then gave the ball after 16 minutes to allow Dries Mertens to drive forward before rolling it into the path of Lukaku to plant it low into the corner.

Tunisia hit back two minutes later with a Dylan Bronn header as Belgium’s own sometimes shaky defending was exposed but another misplaced Tunisian pass enabled Thomas Meunier to feed his goal-hungry striker as Lukaku clipped in to make it 3-1 in stoppage time.

Following his double against Panama it took the him to four goals for the tournament, level with Portugal’s Cristiano Ronaldo, and made him Belgium’s highest scorer at a single World Cup after one-and-a-half games.

An inch-perfect Kevin de Bruyne pass sent Hazard clear for his second six minutes after the restart, the midfielder showing superb balance and skill to round keeper Farouk Ben Mustapha.

Substitute Batshuayi then had a remarkable last 20 minutes, having a shot cleared off the line, hitting the bar inexplicably from point-blank range and having another effort brilliantly saved before finally finding the target in the 90th with a good finish.

“The Belgian team is a superior side,” Tunisian coach Nabil Maaloul said. “We would like to apologise to the Tunisian fans. We did our best and we will try to improve our performance in the future.”