Stoke were no match for their rampant hosts and the much-vaunted threat of Rory Delap's long throw-ins proved almost unfounded.
Almost, because Stoke's only chance of the game came from the Republic of Ireland international's first throw in the 11th minute.
The throw, taken from near the right corner flag, brushed off the head of John O'Shea, at the near post, forcing United goalkeeper Edwin van der Sar into a fine fingertip save.
That was the only time in the game when van der Sar's goal came under any real threat.
United opened the scoring in the third minute when Ronaldo took his United goal tally to the century mark with one of his speciality free-kicks.
Amady Faye brought down Carlos Tevez 30 yards out on the left. Up stepped Ronaldo to score with a viciously swerving right-foot free-kick, which Stoke goalkeeper Thomas Sorensen could only help into the roof of the net.
Ronaldo spelt out the figure 100 in the air, but United had another 42 minutes to wait before breeching the Stoke defence again.
A quick-silver move saw Darren Fletcher and Dimitar Berbatov work the ball to Ronaldo on the last corner on the Stoke box. Ronaldo touched the ball inside to Michael Carrick, who scored with a fierce left-foot shot from 15 yards.
Any hope of Stoke getting a crumb of comfort from the game was ended four minutes after the interval.
Fletcher found Tevez on the right and his cross to the near post saw Berbatov produce an audacious piece of skill to flick the ball up and fire it home right-footed from eight yards past bemused marker Ryan Shawcross and Sorensen.
Stoke worked hard to keep United at bay until the 84th minute when a superb individual goal from substitute Danny Welbeck made it 4-0.
The United striker, making his Premier League debut, still has 11 days to go before celebrating his 18th birthday.
But, picking up a loose ball midway inside the Stoke half, Welbeck advanced to score with a magnificent swerving 30-yard right-foot shot past Sorensen and into the net.
Ronaldo had started the scoring and he completed the rout in the dying seconds.
Shawcross brought down Carrick in a central position 25 yards out and Ronaldo stepped up to curl a brilliant right-foot free-kick around the Stoke wall and into the bottom corner of the net.