Didier Drogba came off the bench to fire Chelsea into the semi-finals of the Carling Cup with a late free-kick.
Frank Lampard congratulates Didier Drogba after his winner
Newcastle went close to taking the lead when an Obafemi Martins drive hit the underside of the bar and bounced down on to the line before being cleared.
Andrei Shevchenko also hit the post for Chelsea but they needed Drogba's curler to break the deadlock on 79 minutes.
Frank Lampard almost added a late second with a 40-yard shot against the post from a poor Shay Given clearance.
Drogba had been one of five of boss Jose Mourinho's 'untouchables' absent at the start of the game.
He joined Ashley Cole, Lampard, and Michael Ballack as substitutes while the injured John Terry missed out altogether.
But the visitors still made a strong start and, not for the first time this season, it was thanks to Michael Essien taking the game by the scruff of the neck in the middle.
He was involved in a slick move that led to Mikel Jon Obi firing over and then scuffed his own shot wide soon after good work by Salomon Kalou.
Newcastle, playing with only Martens up front, had their fair share of possession but looked short of ideas when it came to creating chances.
That all changed after 25 minutes when Martins at last got a sniff of goal.
Receiving the ball from Nolberto Solano some 30 yards out, the Nigerian composed himself before unleashing a dipping drive that smashed against the bar and bounced down and then out before being cleared.
TV replays failed to clear up whether or not the ball had crossed the line but the reaction of Newcastle boss Glenn Roeder showed he knew how close his side had come to opening the scoring.
They were not finished there either, with Nicky Butt unleashing a peach of a volley from the resulting corner that Hilario had to punch away.
That was by far the best spell of the match for the home side though and they were almost behind at half-time, Shevchenko's shot bouncing back off the far post after Essien had played him in.
Lampard was the first of Mourinho's big guns to be brought on, replacing Makelele at the break.
He quickly tested Given with a shot from distance, but was off target with his next effort after Robben found him in space in the area.
At the other end Emre's clever pass set Kieron Dyer free but Hilario came out quickly to block his shot.
Ballack's introduction on the hour mark seemed to give Chelsea another lift but it was the arrival of Drogba - to replace Shevchenko on 75 minutes - that was to prove decisive.
Five minutes later Robben was chopped down by Solano and Nicky Butt's double challenge on the left corner of the area.
Drogba played the ball short to Ballack to open up the angle and then curled in a precise shot that Given could only help into the top corner for his 17th goal of the season.
Newcastle attempted to respond but for all their effort they were still lacking inspiration in the final third.
And Chelsea could have had another before the end when Lampard intercepted Given's careless clearance and was unlucky to see his shot come back off the post with the keeper nowhere to be seen.
Newcastle: Given, Solano, Taylor, Ramage, Huntington, Milner (Sibierski 86), Butt, Parker, Emre, Dyer, Martins.
Subs Not Used: Srnicek, Luque, Rossi, Edgar.
Booked: Emre, Solano.
Chelsea: Hilario, Ferreira, Carvalho, Boulahrouz, Bridge, Kalou, Makelele (Lampard 46), Essien, Robben, Shevchenko (Drogba 73), Mikel (Ballack 66).
Subs Not Used: Hedman, Ashley Cole.
Booked: Ferreira, Boulahrouz.
Goals: Drogba 79.
Ref: C Foy (Merseyside).