John Guidetti drove home the free-kick that followed Pascali's professional foul on Stefan Scepovic.
Kilmarnock keeper Conor Brennan limited the damage with a string of saves for the Ayrshire side.
But he could not prevent Scepovic knocking in a second after the break.
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Pascali's dismissal changed the nature of the match. Before his red card on 34 minutes for pulling Scepovic back as he bore down on goal, the teams had been evenly matched.
Both sides had shown flashes of skill - a Guidetti flick here, an Alexei Eremenko dummy there - but the goalkeepers had been under-employed.
Tope Obadeyi advanced from midfield to offer some threat to Craig Gordon's goal on occasion but was stymied by the alertness of the Scotland keeper or the positioning of Virgil van Dijk and Jason Denayer in the home defence.
Van Dijk headed a corner a fraction wide and Celtic captain Scott Brown broke off from his midfield tussles with Jamie Hamill and Sammy Clingan to fire a few shots at Brennan's goal but they were bravely blocked by defenders.
And Mubarak Wakaso thumped a header straight into Brennan's arms from the corner of the six-yard box.
Gordon's only real save of the first half was to parry a 25-yard pile-driver by Eremenko.
Pascali, who had been the key figure in organising the Killie defence, was lucky when referee Willie Collum awarded him rather than Guidetti a free-kick after making a mess of ushering the ball out for a goal kick with the Swede snapping at his heels.
But the Italian offered little complaint when Collum flashed him a straight red for his panicked challenge on Scepovic.
Killie boss Allan Johnston immediately withdrew Eremenko and sent on Lee Ashcroft to partner Mark Connolly in defence but within seconds Guidetti had stroked his free-kick past the despairing Brennan.
Celtic had Killie on the back foot and the visitors had a close shave when Connolly headed an effort off the line and Brennan saved well from a Stefan Johansen crack from 18 yards.
As the Rugby Park men struggled to play in Celtic's half, so the chances came for the hosts.
Brennan palmed away an angled shot by Scepovic, relied on his post to keep out a Guidetti effort from 12 yards and was well placed, again, to block the centre-forward's effort 10 seconds later.
But the Serbia international would get the last laugh over Brennan, who was in for the injured Craig Samson.
Moments after side-footing horribly wide from 18 yards as Wakaso found space on the left, Scepovic was rewarded for his persistence when he met the winger's cross to hit the ball across Brennan and into the net.
Celtic manager Ronny Deila replaced the scorer with Leigh Griffiths and sent on Charlie Mulgrew for Johansen - but the match was over as a meaningful contest and Celtic were able to follow up Thursday's Europa League win over Astra by moving up to fourth in the Scottish Premiership, overtaking Kilmarnock in the process.
Match ends, Celtic 2, Kilmarnock 0.
Second Half ends, Celtic 2, Kilmarnock 0.
Foul by Virgil van Dijk (Celtic).
Michael Ngoo (Kilmarnock) wins a free kick in the attacking half.
Foul by Jason Denayer (Celtic).
Michael Ngoo (Kilmarnock) wins a free kick in the defensive half.
Corner,  Celtic. Conceded by Conor Brennan.
Attempt saved. Adam Matthews (Celtic) right footed shot from the right side of the box is saved in the bottom right corner.
Attempt missed. Charlie Mulgrew (Celtic) left footed shot from outside the box is close, but misses to the right.
Foul by Jason Denayer (Celtic).
Michael Ngoo (Kilmarnock) wins a free kick in the defensive half.
Foul by Leigh Griffiths (Celtic).
Mark Connolly (Kilmarnock) wins a free kick in the defensive half.
Substitution, Celtic. Aleksandar Tonev replaces Mubarak Wakaso.
Attempt blocked. Leigh Griffiths (Celtic) right footed shot from the centre of the box is blocked.
Foul by Adam Matthews (Celtic).
Michael Ngoo (Kilmarnock) wins a free kick in the defensive half.
Charlie Mulgrew (Celtic) wins a free kick on the left wing.
Foul by Michael Ngoo (Kilmarnock).
Substitution, Kilmarnock. Michael Ngoo replaces Josh Magennis.
Attempt missed. Virgil van Dijk (Celtic) header from the centre of the box is close, but misses to the right.
Corner,  Celtic. Conceded by Ross Barbour.
Substitution, Celtic. Charlie Mulgrew replaces Stefan Johansen.
Substitution, Celtic. Leigh Griffiths replaces Stefan Scepovic.
Attempt blocked. Stefan Johansen (Celtic) right footed shot from outside the box is blocked.
Attempt saved. Stefan Scepovic (Celtic) right footed shot from outside the box is saved in the top right corner.
Attempt saved. Mubarak Wakaso (Celtic) right footed shot from outside the box is saved in the bottom left corner.
Goal!  Celtic 2, Kilmarnock 0. Stefan Scepovic (Celtic) right footed shot from the right side of the six yard box to the bottom left corner. Assisted by Mubarak Wakaso.
Attempt missed. Stefan Scepovic (Celtic) right footed shot from outside the box is close, but misses the top left corner.
Jason Denayer (Celtic) wins a free kick in the attacking half.
Foul by Josh Magennis (Kilmarnock).
Corner,  Celtic. Conceded by Lee Ashcroft.
John Guidetti (Celtic) hits the left post with a right footed shot from the centre of the box.
Attempt missed. Jamie Hamill (Kilmarnock) right footed shot from more than 35 yards is just a bit too high.
Ross Barbour (Kilmarnock) is shown the yellow card.
Mubarak Wakaso (Celtic) wins a free kick on the right wing.
Foul by Ross Barbour (Kilmarnock).
Stefan Johansen (Celtic) is shown the yellow card.
Foul by Stefan Johansen (Celtic).
Jamie Hamill (Kilmarnock) wins a free kick in the defensive half.
Kilmarnock paid heavily for the first-half sending-off of their captain Manuel Pascali as Celtic jumped to fourth in the Scottish Premiership with a comfortable win.