By Alasdair LamontBBC Sport Scotland at Celtic Park
A brace from the in-demand Gary Hooper helped secure the points for Celtic.
The striker wanted by Norwich scored early from close in and sealed victory with a goal five minutes from time.
Georgios Samaras gave Celtic a two-goal lead in 12 minutes, but Hearts gave Celtic a scare when Jason Holt's deflected shot reduced the deficit.
Hooper's late contribution put the game beyond the visitors and substitute Lassad rounded off the scoring in style in injury time.
Celtic had looked in the mood from the off and delivered notice of their intentions within 90 seconds.
Adam Matthews took advantage of a kindly break of the ball inside the box to roll the ball to Hooper, who stretched to tap into Jamie MacDonald's empty net.
Celtic were exploiting a weakness down Hearts' left and that was the source of the home side's second, with only 12 minutes on the clock.
Kris Commons got away from Kevin McHattie, though the Celtic player was fortunate not to be penalised for pulling his opponent back.
The referee Iain Brines saw nothing wrong and Commons' shot from inside the box was parried by MacDonald, but only into the path of Samaras who simply had to roll the ball into the empty net.
Celtic were utterly dominant and only occasional carelessness gave Hearts the slightest glimmer of hope.
New Celtic signing Rami Gershon was an unused substitute.
The home side should have had at least a third goal before half-time, with Commons scuffing a shot straight into the arms of MacDonald and then Joe Ledley having an effort blocked by Andy Webster, with the goalkeeper grounded.
Jamie Walker was introduced at half-time by John McGlynn in place of Callum Paterson and he instantly made an impression, forcing Lukasz Zaluska into action for the first time in the game, the Pole saving low to his right.
Hooper thought he had his 20th goal of the season when he converted Commons' cross from the left, but an offside flag curtailed his celebrations.
Celtic should have been celebrating a third goal just before the hour mark when Matthews picked out the unmarked Scott Brown eight yards from goal, but the captain's diving header was well off-target.
Moments later, MacDonald produced a superb save to keep out Ledley's powerful shot - the culmination of another excellent Celtic move.
Having failed to put the match beyond the visitors, Celtic found their lead halved on 69 minutes.
Holt picked up a long clearance from MacDonald and with the Celtic defenders trying to close him down, he poked the ball goalwards and courtesy of a wicked deflection, found the bottom right corner of the net.
Hearts searched for an equaliser in vain and Hooper did get his 20th goal of the campaign, firing low past the keeper after a powerful run by Brown down the right.
Lassad gave the scoreline a more impressive look in injury time when he found the net in stylish fashion from a tight angle, beating MacDonald with a beautifully controlled finish.
Hearts gave their all throughout, but were ultimately outclassed, though the addition of Danny Wilson already looks an astute one by John McGlynn.
Goal! - Lassad Nouioui - Celtic 4 - 1 Hearts Lassad Nouioui finds the net with a goal from close range to the top left corner of the goal. Celtic 4-1 Hearts.
Emilio Izaguirre produces a cross,
Victor Wanyama challenges Jason Holt unfairly and gives away a free kick. Jason Holt takes the free kick.
Corner taken left-footed by Charlie Mulgrew, Victor Wanyama has a headed effort at goal,
Substitution Dale Carrick on for Mehdi Taouil.
The assist for the goal came from Scott Brown.
84:40 Goal scored
Goal! - Gary Hooper - Celtic 3 - 1 Hearts Gary Hooper fires in a goal from close range to the bottom left corner of the goal. Celtic 3-1 Hearts.
Substitution Kris Commons leaves the field to be replaced by Thomas Rogne.
Free kick awarded for a foul by Beram Kayal on Callum Tapping. Andy Webster takes the indirect free kick.
Andrew Driver crosses the ball, save by Lukasz Zaluska.
The ball is sent over by Kris Commons, save by Jamie MacDonald.
Kris Commons fouled by Callum Tapping, the ref awards a free kick. Scott Brown takes the indirect free kick.
The offside flag is raised against Kris Commons. Jamie MacDonald takes the indirect free kick.
Kris Commons takes the direct free kick. Corner from the right by-line taken by Kris Commons, clearance made by Jason Holt.
Substitution Lassad Nouioui is brought on as a substitute for Adam Matthews.
Booking Kevin McHattie booked.
Free kick awarded for a foul by Kevin McHattie on Scott Brown.
Darren Barr concedes a free kick for a foul on Georgios Samaras. Charlie Mulgrew takes the direct free kick.
Emilio Izaguirre crosses the ball, Victor Wanyama has a headed effort at goal from deep inside the area missing to the right of the goal.
The referee gives a free kick against Andrew Driver for handball. Indirect free kick taken by Adam Matthews.
Scott Brown challenges Jason Holt unfairly and gives away a free kick. Free kick taken by Mehdi Taouil.
Substitution Callum Tapping joins the action as a substitute, replacing Dylan McGowan.
Booking Darren Barr is cautioned by the ref for unsporting behaviour.
The ball is crossed by Georgios Samaras, Danny Wilson manages to make a clearance.
Georgios Samaras delivers the ball, Danny Wilson manages to make a clearance.
Assist by John Sutton.
68:16 Goal scored
Goal! - Jason Holt - Celtic 2 - 1 Hearts Jason Holt grabs a goal from inside the penalty area to the bottom left corner of the goal. Celtic 2-1 Hearts.
The ball is sent over by Emilio Izaguirre, Georgios Samaras takes a shot. Save made by Jamie MacDonald.
Substitution (Celtic) makes a substitution, with Beram Kayal coming on for Joe Ledley.
Jamie Walker produces a left-footed shot from inside the area that clears the crossbar.
The ball is sent over by Kris Commons, Jamie MacDonald makes a comfortable save.
Georgios Samaras delivers the ball, Joe Ledley takes a shot. Save by Jamie MacDonald. Outswinging corner taken left-footed by Kris Commons, Jason Holt makes a clearance.
Adam Matthews produces a cross, Close range header by Scott Brown goes wide of the left-hand upright.
Darren Barr fouled by Emilio Izaguirre, the ref awards a free kick. Andrew Driver restarts play with the free kick.
Victor Wanyama challenges Jason Holt unfairly and gives away a free kick. Andrew Driver crosses the ball from the free kick left-footed from left wing, clearance made by Charlie Mulgrew.
The referee blows for offside against Gary Hooper. Jamie MacDonald takes the free kick.
The official flags Gary Hooper offside. Free kick taken by Jamie MacDonald.
Jamie Walker has an effort at goal. Save made by Lukasz Zaluska.
Gary Hooper sends in a cross, clearance made by Darren Barr. Outswinging corner taken left-footed by Kris Commons from the left by-line, John Sutton manages to make a clearance. Corner taken by Kris Commons from the left by-line, Scott Brown takes a shot. Andy Webster gets a block in.
Andrew Driver crosses the ball.
The referee blows his whistle to start the second half.
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