Costa Rica stunned the hosts to take an unlikely lead in the 24th minute before Lukaku got on the end of a pinpoint Dries Mertens - the scorer of the equaliser - delivery to power home an unstoppable volley from inside the box.
Los Ticos' advantage lasted only seven minutes, though.
But that was the visitor's only effort of note, and seemed to compose the home side, who took charge nearly immediately.
Which team are you supporting in the 2018 World Cup? To get the latest soccer news, text "SPORTS" to 22840.
The Chelsea striker had only been on the field for 12 minutes when Lukaku unselfishly laid the ball into his path for a simple finish, following some impressive build-up play from Hazard through the middle.
The Manchester United hitman, his country's record scorer, turned his 35 global goals into 36 just five minutes into the second period.
It was Chadli who provided the centre from the same flank for Lukaku to score his second five minutes into the second half, though he surprisingly passed up the opportunity to grab a hat-trick soon after, instead squaring the ball across for Batshuayi to tap home.
Costa Rica struggled to contain the movement of the Belgian attack, who always looked capable of opening up their opponents when stepping through the gears.
This time Lukaku, bearing down on Navas, eight yards from goal, squared to tee up his teammate, who rolled home.