Young, after being picked out by Evra, seeing his close-range effort blocked when a goal looked the only outcome. A second strike for United did indeed follow a minute later.
After a United corner had initially been cleared, Young found Cleverley on the right and his whipped cross was met by Smalling who hung brilliantly in the air and guided a header past Wang in the Kitchee goal despite the keeper getting a hand to it.
On 26 minutes the Reds made it three with a goal of the highest quality. And Zaha was involved once more. After receiving the ball on the right, the winger flicked a sublime pass with the outside of his right boot into the box to the onrushing Fabio who followed suit with an identical finish past Wang.
Welbeck and Smalling went close to a second apiece on the half hour-mark, but it remained 3-0 up until the break.
Moyes made three changes at the start of the second period with Alexander Büttner, Jesse Lingard and Adnan Januzaj replacing Evra, Young and Welbeck respectively.
Having caught the eye already during pre-season, Januzaj took just five minutes to do so again, this time with his first ever senior goal. Büttner scampered down the left before chipping the ball up to Januzaj who expertly directed a header past Wang.
Kitchee didn’t let the early second-half setback derail them and they got themselves on the scoresheet on 58 minutes thanks to a sublime strike by Lam. Having collected possession in United’s half he twisted and turned before letting fly with a 20-yard belter into the top corner past the helpless Ben Amos.
Januzaj twice went close to netting his second of the game with two efforts well saved by Wang. Kitchee, meanwhile, buoyed by Lam’s upped the tempo in attack and on 68 minutes United’s earlier four-goal lead was halved thanks to Alex Alkande’s superb run and finish.