The Red Devils just need England to avoid defeat to Panama in Sunday's other Group G game to confirm their last-16 spot and no team at Russian Federation 2018 will want to be drawn against Roberto Martinez's side after this swashbuckling display. Penalty for Belgium. Eden Hazard takes it and scores against Tunisia in the 6th minute.
He scored twice in Belgium's 3-0 opening Group G game against Panama and needed just 45 minutes against Tunisia to score another double.
Belgium had a two-goal lead within 16 minutes.
Should they lose their final game against England, now on three, and pointless Panama somehow beat England and Tunisia, all three would have six points and the top two would be decided on goal difference.
Tunisia captain Wahbi Khazri got his team's second with nearly the last kick of the match.
Beating a star-studded Belgium team looks a tough ask for Tunisia, who may well become the latest nation to see their World Cup dreams end on Saturday.
Hazard then ran on to a long pass in the 51st minute, flicked the ball around Ben Mustapha and shot into an empty net.
With half-time approaching, the Belgians grabbed their third goal.
Michy Batshuayi closed in on his first World Cup goal, but his attempt was cleared off the line after rounding Mustapha 14 minutes to full-time.
Khazri scored a consolation deep into stoppage time after a neat swivel in the box, but it mattered little as Belgium comfortably took a giant stride towards the last 16.