Chelsea provided further evidence that their soft underbelly has been consigned to the past as they overcame a tricky fifth round tie at a packed Britannia Stadium.
Stoke, taking time out from their first division relegation battle, fought for every ball and at times looked capable of springing a surprise.
But Claudio Ranieri's stars stood up to be counted and always looked worthy winners once Jimmy Floyd Hasselbaink broke the deadlock in the 52nd minute.
The Blues found it tough going against City's massed ranks in the first half with a Mario Stanic header, well saved by Steve Banks in the 12th minute, providing their only real serious threat.
Stoke created two decent chances themselves as James O'Connor and Lewis Neal both failed to hit the target when well placed.
And the underdogs made a promising start to the second half with Neal forcing Carlo Cudicini's only real action of the afternoon with a well struck free kick from 20 yards.
Chelsea put one foot in the last eight when Hasselbaink struck on his first start since limping off at Old Trafford last month.
The ball bounced into his path off the unfortunate Marcus Hall and the Dutchman placed a slide rule finish inside Banks' left hand post.
Stoke refused to throw in the towel and their man of the match O'Connor fired over the top after bursting clear.
But Chelsea wrapped up the tie 14 minutes from time when Eidur Gudjohnsen sent substitute Jesper Gronkjaer racing clear and the Danish winger blasted his shot inside Banks' near post from ten yards out.
Afterwards Ranieri said: "The players showed a lot of character and they had to. It is very pleasing to see us play at the same level and with the same attitude in every game."Stoke boss Tony Pulis said: "I was very pleased with the performance. If we play like that for the last 15 games, we will stand a good chance of staying in the first division."