The Belgian netted twice on an afternoon when Chelsea team-mate Gonzalo Higuain opened his Premier League account with a double of his own.
But Hazard was the standout man, the manner in which he effortlessly glided his way through a sea of yellow shirts time and time again giving new head coach Jan Siewert a first hand taster of just how tough life can be in the top flight of English football.
Town, despite giving the hosts a couple of anxious moments in the first half, were well beaten by the Blues and could have lost by an even bigger margin.
Argentinian striker Higuain, on loan from Juventus, broke the deadlock in the 16th minute with a razor sharp finish.
N’Golo Kante created the opportunity with a delightful pass that left the Terriers defence flat-footed.
Higuain also fired into the side-netting during a first half in which the hosts did most of the pressing as Jonas Lossl made saves from Eden Hazard and Cesar Azpilicueta.
Town, though, still had their moments with Aaron Mooy heading over from a Chris Lowe cross and Philip Billing having a shot blocked after good work from Adama Diakhaby.
Chelsea doubled their advantage on the stroke of half-time through Hazard from the spot after Azpilicueta had been fouled by Elias Kachunga.
After that, it was all about how big the winning margin would be. Hazard doubled his goal tally with a finish from a tight angle on 66 minutes, the Belgian having skipped past goalkeeper Jonas Lossl following good approach play from Ross Barkley and Kante.
Kante was also involved in the fourth goal three minutes later, his lay-off teeing-up Higuain for a quite exquisite finish from 25 yards that gave Lossl no chance.
Kachunga then diverted a David Luiz header past Lossl to cap a miserable afternoon in the capital for the Terriers.
Siewert said: “I don’t feel well at the moment. We came here to give a big fight.
“The first chance to Aaron Mooy showed we wanted to win the game, but at the moment you can’t compare us to Chelsea.
“We lost 5-0. That shows that Chelsea were quite angry after the Bournemouth game and showed it, so it was a bad time to play them.”
Chelsea’s penalty appeared soft after contact between Kachunga on Cesar Azpilicueta which began outside the box.
“I’m not quite sure whether it was a penalty,” said Siewert, who was uncertain at the severity of Isaac Mbenza’s calf injury.
“Every Chelsea player went away. No one expected it.”