Hazard scored the opener on a sixth-minute penalty, converting after he was taken down just inside the right of the area by Syam Ben Youssef.
Lukaku, who also had a brace against Panama on Monday, has scored 17 goals in his last 11 worldwide games, Hazard scored his first two World Cup goals with a penalty in the opening minutes and Michy Batshuayi capped off the scoring late.
Two goals each for Romelu Lukaku and Eden Hazard and one for Michy Batshuayi swept Belgium to a 5-2 victory over Tunisia on Saturday that put them in command of World Cup Group G and underlined their status as one of the tournament favourites. Dylan Bronn and captain Wahbi Khazri were on target for Tunisia.
Saudi flat ahead of MSCI decision; other markets down
If Saudi gets the nod, reclassification would happen in two steps as part of MSCI's May and August 2019 reviews. Maurel estimates it will lead to $35 billion of inflows.
Belgium coach Roberto Martinez will field the same starting XI which beat Panama 3-0 on Monday, hoping for three points that would all but qualify his side for the next round before they face England on Thursday.
Belgium and England clash next Thursday in their final Group G match in Kaliningrad in a contest likely to decide the pool victor. Lukaku finishes it coolly to give Belgium a 2-0 lead over Tunisia in the 16th minute.
If Belgium beats Tunisia it will be nearly certainly assured of a place in the knockout stages of the World Cup. On Sunday, a draw for England against Panama would knock the African team out of the World Cup.
Ahmed Musa sets TWO World Cup records as Nigeria beat Iceland
With the "Fubo Premier" bundle, you will get access to all four of the World Cup soccer TV channels in most markets. "When I see the matches are so hard then we have to learn also it is not finished after this World Cup for us".
It was the second-earliest goal scored by a Belgium player at a World Cup after Leopold Anoul scored in the fifth minute in 1954.
In the only other change, Naim Sliti has been replaced on the left wing by Saif-Eddine Khaoui.
Suspect in XXXTentacion Shooting Taken into Custody
No motive was announced in Williams' arrest but police have previously said the shooting was an apparent robbery attempt. The Broward County Sherriff's Office had offered a $3,000 (£2,200) reward for any information about the killing.