Gareth Taylor's side were aiming for a seventh successive victory in all competitions, and got things off to a dream start when Julie Blakstad tapped home from close-range for her second goal in as many matches.
But City had to wait until after the break to add to our advantage, with the visitors also going close before half-time with a header from Brianna Westrup.
The hosts' quality would eventually tell though, when Hayley Raso doubled our advantage within two minutes of the restart after latching on to a long ball over the Sunderland defence.
And number three would follow soon after when Khadija 'Bunny' Shaw slotted home her 11th goal of the campaign after being played through by captain Steph Houghton.
City could have added to our lead with the Jamaican, Blakstad and young substitute Lois Marley-Paraskevas all going close, but were forced to settle for a three-goal victory at the Academy Stadium.
Check out the best of the action via the video above...
BARCLAYS WSL ETIHAD DERBY: GET YOUR TICKETS
CITY V UNITED: ETIHAD DERBY
City welcome Manchester United to the Etihad Stadium on Sunday 11 December.
Kick-off is scheduled for 12:30 (UK), with tickets selling fast for our third-ever women's match at the Etihad.
We hosted Everton there back in May 2014, before welcoming our local rivals in September 2019, when Caroline Weir’s wonder strike saw us run out 1-0 winners in front of what was then a WSL record crowd, and what remains a club record of 31, 213 fans.
With almost 40,000 tickets already sold, it promises to be another historic occasion.
You can secure your tickets online by visiting: www.mancity.com/tickets/womens or by calling: +44 (0)161 444 1894.