A Hazard penalty and a goal from Lukaku gave Belgium a quickfire 2-0 lead, although they were pegged back by a Dylan Bronn header for Tunisia. However, Lukaku restored the two-goal advantage on the stroke of half time with a fine finish, putting him level with Cristiano Ronaldo in the race for the Golden Boot.
After the break Hazard made the game safe with his second of the day. With the clock ticking down, Michy Batshuayi added more gloss to the scoreline with Belgium's fifth. Tunisia skipper Wahbi Khazri scored a late consolation for his side.
Belgium now top Group G on six points. England have the chance to move level with the Red Devils on Sunday, when they face minnows Panama.
Ronaldo Still the Main Man, But Lukaku Getting Closer
Ahead of this encounter, Portugal's Cristiano Ronaldo was out on his own in the race for the Golden Boot at the 2018 World Cup. By half-time, Lukaku was level with him.
After a brace against Panama in the opening game, the Manchester United man continued where he left off. He finished well with his left foot after being played in in the 16th minute, before giving his team breathing room on the stroke of half-time with a dinked right-footed effort:
As noted by Samuel Luckhurst of the Manchester Evening News, he's in red-hot form for his country at the moment:
Meanwhile, Kristan Heneage praised the dynamic forward's intelligent movement in a stunning first-half performance:
With the likes of Hazard, Kevin De Bruyne and Dries Mertens supporting Lukaku, the chances should flow regularly for him throughout the tournament.
The Belgium No. 9 has showcased the potency in front of goal to fire his nation far in the World Cup. In the knockout stages and the huge games, the challenge will be for Lukaku to continue up this prolific form—something Ronaldo has done so well throughout his career.
World-Class Hazard Will Inspire Deep Belgium Run
Lukaku's assault on the Golden Boot will grab the headlines after this game, but the contribution of the imperious Hazard shouldn't be underestimated.
Against Panama, he started poorly and grew into the game. In this match, he was at full tilt from the off, winning the early penalty then calmly converting it. Early in the second half, he latched on to Toby Alderweireld's long pass, rounded the 'keeper and finished with aplomb.
As noted by Fox Sports' Keith Costigan, the manner in which Hazard and Lukaku linked up bodes well for Belgium:
Up top, the Red Devils have Lukaku to stick the ball in the back of the net, and in midfield, De Bruyne controls the tempo of matches. Hazard, as he did here, is the man who knits everything together.
It appears the Belgium captain is growing into the tournament. Should Hazard continue to improve, he'll take his nation a long way.
Defensive Cracks Will Ultimately Cost Belgium
While there was much to marvel at from an attacking perspective from Belgium, they did showcase weaknesses defensively that will have stronger nations rubbing their hands together.
After surging into a 2-0 lead, the Red Devils switched off immediately from a set piece, from which Bronn headed home.
There was clear complacency from the Red Devils:
In general play, there were also moments when Tunisia did carve out good openings, only for their lack of quality to let them down.
Former Wales international Danny Gabbidon believes they will be caught out in the channels:
The big concern for Martinez's Belgium side has always been whether they can find the balance between defence and attack, something they've not had to do against two weak outfits so far.
While they were excellent here, they must shore up defensively if they are going to go all the way. Against stronger opponents, their attack will be better contained and the holes in their 3-4-3 setup better exploited.
The four teams finish their group stage matches on Thursday, with Belgium and England meeting in what should be a showdown to see who tops the group.
Tunisia, meanwhile, at least have a chance to earn their first World Cup win since 1978; they meet Panama in their final contest. This is Los Canaleros' first appearance in the tournament.