Just after the half-hour mark, Haaland doubled the lead with a towering header from Kevin de Bruyne's corner and just three minutes later, the number nine added a third with a stretching finish, marking his 13th Premier League goal after just eight matches.
De Bruyne provided the assist again, taking his total top-flight assist tally to 94 in 218 appearances.
City were rampant and just before the interval, Foden connected to Haaland's teasing cross at the back post to add a fantastic fourth, the Englishman's 50th goal for his boyhood club.
The visitors emerged from the interval well and pulled a goal back through Antony's spectacular long-range strike.
Just after the hour mark, Haaland completed his third successive home hat-trick, the first player in the history of the Premier League to do so, powering beyond David de Gea from a driven Sergio Gomez cross.
With just over 15 minutes remaining, Foden completed his treble, latching onto Haaland's pass to drill in our sixth of the afternoon.
United made in 6-2 after 84 minutes, with Anthony Martial nodding in after Ederson parried Fred's powerful shot.
With the clock ticking into stoppage time, Martial netted again, this time from the penalty spot.
City claimed the three points after a nine-goal thriller - view the best images from the game via the gallery below.