City dominated United from the first whistle, keeping possession neatly and fashioning a host of chances to repeatedly break the visitors down.
It took just eight minutes for the scoring to get underway as Foden fired in an effort before Haaland netted twice after the half-hour mark.
England international Foden then scored his second to put give City a resounding 4-0 lead at half-time, with a host of United fans captured leaving the stadium having already seen enough.
Erik ten Hag's stricken side put themselves on the board after the break through an excellent strike from Antony (22), but things would revert back shortly.
Haaland completed his hat-trick on 64 minutes to become the first City player to hit a treble against United since Francis Lee's efforts in 1970.
Foden would follow up the Norwegian to notch his own hat-trick minutes later, while substitute Anthony Martial (26) would add two late consolation goals on what was a torrid afternoon for United.
The win put Pep Guardiola's men back to within one point of Premier League leaders Arsenal, while United remain in sixth.
Here are five talking points from Sunday's nine-goal thriller in Manchester.
Haaland train rolls on
It was yet another performance from Haaland that set the tongues wagging.
He continued to demonstrate his impressive knack for being in the right place at the right time, making it virtually impossible for any United defender to stop him.
A third consecutive hat-trick at home in the Premier League has taken his tally up to a ridiculous 13 goals in just eight games, and he doesn't appear to be slowing down.
But it wasn't just Haaland's goal-scoring ability on show, playing a key role in two of Foden's strikes with a couple of tidy balls in.
City's hat-trick heroes
While Haaland will be celebrating his hat-trick contribution to City's thumping win, it came with the added bonus of a record being broken.
Not only did Haaland become the first player in league history to score three at home in as many games, but he also became just the third City player to put three past United shortly before Foden emerged as the fourth.
The pair made it look so easy on the day when a number of their finishes were anything but, and it will give Guardiola a sense of confidence knowing he has another forward capable of chipping in with goals.
United's full-backs decimated
It was a forgettable afternoon for the vast majority of United players on the pitch at the Etihad and that was certainly the case for their full-back pairing of Diogo Dalot (23) and Tyrell Malacia (23).
The former was booked just two minutes into the game for a cynical foul on Jack Grealish (27) and never managed to recover as he was bombarded further into proceedings.
It was an equally poor display from Malacia at left-back, who massively struggled to deal with Foden's movement throughout before he was hauled off at half-time.
Ronaldo left unused
Time on the bench has never been much of a feature of Cristiano Ronaldo's (37) storied career, and yet that's where he has found himself so far this season.
The Portuguese star has been used sparingly by Ten Hag, with his only league start coming in the 4-0 hammering at Brentford, but things stooped lower against City.
Starting from the bench, Ronaldo was snubbed completely in the derby and was left unused despite United needing some form of inspiration to avoid total humiliation.
And an even more bitter taste will have been left given the fact that Ten Hag used all five of his substitutes ahead of him.
Highest scoring Manchester derby
The latest edition of the derby was more than value for money for the neutral, with nine goals in a single fixture a rarity.
But there was an added caveat in that the 6-3 result featured the most goals ever scored in a single Manchester derby - with seven goals being the previous record.
