Newcastle took Manuel Pellegrini’s side to added time and probably had the better of things over 90 minutes, but they could not break the deadlock and instead were left digesting an unflattering 2-0 defeat. And while City’s strike pair must take their share of the praise for neat finishes in the 99th and 115th minutes, Pantilimon also did everything that was asked of him.
City made 10 changes from the side beaten by Chelsea, the least surprising saw struggling Hart stepping down.
A first-half save by Pantilmon from Shola Ameobi, when partially unsighted, was good but a firm block when second favourite in a one-on-one with Papiss Cisse was even better.
Newcastle showed five changes of their own, with Yohan Cabaye, Hatem Ben Arfa and Loic Remy all on the bench. The chosen XIs contested a scrappy 90 minutes, with neither doing enough to seal the win in regulation.
Both had chances to do so, though, not least a pair of close-range headers in the space of a minute at the death. Negredo saw his beaten clear by Tim Krul, but an unmarked Yoan Gouffran had no such excuse as he diverted Mathieu Debuchy’s cross wide.
City’s evening could have started embarrassingly, Joleon Lescott almost tripping on the ball as he carried it out of defence after just a minute. Ameobi was lurking but Lescott was able to recover composure to spare his blushes.
Newcastle had a more conventional attempt in the ninth minute when Ameobi headed on for Cisse and the Senegalese striker prodded just wide.
Moments later Stevan Jovetic was forced off injured, with Pellegrini summoning Negredo from the bench.
With City starting lethargically the hosts went close again on the half hour, but Pantilimon saved well from Ameobi. A minute later Ameobi had the ball in the net but was ruled offside when he tapped home Cisse’s shot across goal.
As it was the sides went in goalless, Vurnon Anita also going close for the hosts with a snap volley and Micah Richards ending the half with a strong run followed by a weak shot.
Pantilimon made a comfortable save early in the second half, Anita trying his luck from distance, and there were signs of life from City in attack as the previously anonymous Jesus Navas began to see more of the ball.
Navas created City’s best chance in the 63rd minute when he came away with the ball following an ill-judged foray from Krul. With the goal open Navas laid the ball back for James Milner but he curled wide.
Both sides raided their bench in a bid to avert added time, David Silva, Cabaye and Ben Arfa bringing added flair but not the desired result.
With 12 minutes left in normal time Negredo waltzed into the box and floating in a delicate close-range chip that Krul flicked around the post.
Either side might still have won it in normal time, Negredo denied by Krul at close range and Gouffran nodding a glorious chance wide.
Pantilimon made sure the shutout continued in extra-time when he came out to save well from Cisse.
That paved the way for the belated opener, a relatively simple affair that saw Dzeko drill a low cross into the Newcastle area, where Negredo applied the finishing touch.
The Spaniard first had to edge in front of Mapou Yanga-Mbiwa, who will be disappointed to have lost the battle with such ease.
Dzeko got his own reward just before the break in extra-time by getting on the end of Milner’s pass and successfully rounding the keeper as City march on.
NEWCASTLE: Krul, Debuchy, Haidara (Dummett 45), Anita, Williamson, Yanga-Mbiwa, Sissoko, Tiote, Cisse, Sh Ameobi (Ben Arfa 67) Gouffran.
MAN CITY: Pantilimon, Richards (Zabaleta 83), Kolarov, Rodwell (Silva 64), Boyata, Lescott, Navas, García, Dzeko, Jovetic (Negredo 10), Milner.
Referee: Neil Swarbrick.