As promised, Pep Guardiola called on City's academy, handing five players – including all four defenders – their debuts.
That inexperience proved a vulnerability when Brandon Hanlan gave third-tier Wycombe the lead 22 minutes in, but City's quality up front told as it regained control by half-time.
Kevin De Bruyne restored parity with a superb finish before Riyad Mahrez and Phil Foden made life more comfortable for the holder.
Ferran Torres got in on the act and Mahrez grabbed a second to put the result beyond all doubt, with Cole Palmer's first senior goal adding further gloss.
City missed some presentable chances early on and was made to pay. Zack Steffen's weak punch from a corner fell to Ryan Tafazolli, who squared to the unmarked Hanlan to lash home.
Sparked into life, however, City hit straight back – De Bruyne finding the right-hand corner after cutting in from the left after Foden's pass.
A venomous Raheem Sterling effort cracked against the left-hand post as City clicked into gear, with the same upright then denying De Bruyne a second.
Yet Wycombe's luck ran out prior to half-time. Joshua Wilson-Esbrand capped off an impressive run by squaring for Mahrez to sweep home, before the power on Foden's strike did for Wycombe goalkeeper David Stockdale.
Anthony Stewart tried his luck from range as Wycombe searched for a way back into the game, before Jordan Obita was denied by Steffen.
Any slender comeback hopes were swiftly ended, though, with Foden sliding across for Torres to tuck in from close range.
There was time for more, Mahrez helping himself to a second before substitute Palmer rounded off an emphatic win with a crisp finish.