The Belgians were first on the ascendancy after Romelu Lukaku latched onto a long ball to draw a save from Farouk Ben Mustapha in the opening minutes.
The ball continued rolling for the Red Devils as Eden Hazard earned Belgium a penalty after five minutes. The skipper then duly converted from 12-yards to put them on course for back-to-back victories.
Belgium were surging closer to a second, and it didn’t take them long to get it as Lukaku steered home a pass from Dries Mertens just before 20 minutes.
The Carthage Eagles put themselves back in the swing of things courtesy of Dylan Brodman, who headed home from a free-kick with their first shot on goal.
At the other end, Carrasco provided a dangerous scare as he almost restored their two-goal cushion but Mustapha pulled off a breathtaking save.
With the last touch of the half, Lukaku reimbursed their two-goal advantage with a deft chip over an advancing Ben Mustapha.
It was 4-1 six minutes into the second half, as Hazard seized the initiative to get behind two defenders for an easy conversion after rounding Mustapha following a through pass from Toby Aldeweireld.
Carrasco targeted a fifth for them, but after showing good composure to bring the ball down, fired wide of the keeper’s reach.
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.
Batshauyi was denied yet again right in front of goal this time, as he struck the crossbar from point-blank range following a fine cross from Carrasco.
The Belgian striker wasn’t to be denied in the end, though, as he made sure he got his name on the score-sheet with a sliding finish a minute to added time.
Wahbi Khazri found a second consolation for the Tunisians after steering home a cross-field pass a minute from time.
Tunisia: Ben Mustapha - Bronn, S. Ben Youssef, Meriah, Maaloul - Skhiri, Sassi, Khaoui - Badri, F. Ben Youssef, Khazri.