Goals from Neill Collins, Dean Whitehead and Anthony Le Tallec made sure there was to be no shock by the non-league side, who stuck gamely to a task made all the harder by conceding a sixth-minute goal.
But for some wasteful finishing and some brilliant saves from goalkeeper Kris Rogers the Black Cats would have reached double figures, such was their dominance.
Suspensions forced Sunderland into a new partnership in central defence, Alan Stubbs and Neill Collins, recalled from a three-month loan spell at Hartlepool, coming in for skipper Gary Breen and Steve Caldwell.
And it was Neill Collins who gave the Premiership strugglers the dream start they needed to settle the nerves. Liam Lawrence's corner prompted a goalmouth melee and when Whitehead's shot was charged down, the defender lashed the loose ball into the roof of the net.
Only a brave save by Rogers at the feet of Jon Stead, who also had a shot on the turn blocked, had prevented an even more encouraging start for the Black Cats.
Stead headed over from a Lawrence corner and then again turned cleverly to shoot narrowly wide as the Black Cats maintained their all-out assault on the non-league side's goal.
The industrious Stuart Elliott hit a low drive just past the post but it was his former Newcastle United colleague Paul Brayson who came closest to snatching a surprise equaliser in the 32nd minute, Kelvin Davis flinging himself to his left to turn a low free-kick behind for a corner.
Sunderland immediately swept to the other end, where Le Tallec forced a brilliant save from Rogers before Stead crashed the loose ball against the upright.
But the Black Cats were not to be denied and deservedly swept into a two-goal after 41 minutes. The hard-working Stead broke free on the right and his low cross was swept home in style by Whitehead.
Two minutes later, however, they needed the brilliance of Davis protect the lead. The tricky Carlos Roca surged forward to find Johnny Allan, who was denied by the alert home keeper.
There was no let up in the second half and the luckless Stead, still searching for his first goal since his close season transfer from Blackburn Rovers, had a low drive saved, before a rasping drive from Elliott whistled past the post at the other end.
It took a goal line clearance by Justin Hoyte to protect the two-goal advantage and just to rub salt into Northwich's wounds, Le Tallec forced the ball into the net in the next minute.
Stead cut the ball back from the byline and when Rogers could only block Lawrence's effort, Le Tallec made no mistake.
A delicate chip from Lawrence bounced off the top of the crossbar and substitute Daryl Murphy was guilty of a glaring miss in front of goal, while at the other end only a superb save from Davis prevented Elliott from grabbing a late consolation goal for Northwich.
Man of the Match:
Sunderland: Dean Whitehead
The former Oxford United trainee showed exactly why Liverpool are chasing his signature as he bossed the midfield.
Northwich: Stuart Elliott
The ex-Newcastle man worked tirelessly and it took some impressive goalkeeping to prevent him getting his name on the scoresheet.