He grabbed the first three on the night before Joao Cancelo netted the fourth, while Julian Alvarez scored the fifth and sixth in a game that was simply too easy for Pep Guardiola’s side.
City started impressively and the visitors struggled to get on the ball in the opening stages, or out of their own half, such was the relentlessness of City’s attacks.
The opening goal, which came after 12 minutes, was inevitable, as was the goalscorer. It was Haaland who got a toe to Phil Foden’s deep cross and prodded it into the back of the net, while simultaneously holding off Forest captain Joe Worrall.
It was two soon after, as again Foden and Haaland combined to devastating effect, although Nico Williams got the final touch before the latter knocked it into the back of the net, with the Forest defender’s tackle rolling perfectly into Haaland’s path only a few yards out from goal.
City had the ball in the back of the net just before the half-hour mark, but John Stones had wandered offside before touching in Haaland’s header at the back post, and it was chalked off.
But on 39 minutes, it was then Haaland who touched in Stones’ and nodded in a second hat-trick in just five days. The former Borussia Dortmund forward rose highest from a few yards out and headed in to give him a sixth goal in his last 90 minutes of football.
Alvarez, starting his first City game, nearly got in on the act minutes before half-time, when he hit the post with a left-footed strike from the edge of the area.
But within five minutes of the second half it was 4-0. This time Bernardo Silva floated in off the right wing and picked out Cancelo around 20 yards out. The full-back was given far too much time to pick a spot and arc a shot past Dean Henderson.
Other than a Renan Lodi shot which hit the side netting, Forest had offered little going forward, but on 57 minutes Ederson was forced into a first save of the night when he got down well to hold a deflected Morgan Gibbs-White effort.
Eight minutes later and City had another, as Riyad Mahrez’s through ball released Alvarez behind the Forest backline and he then powered a strike into the bottom corner.
There was another goal for City fans to savour, as Alvarez made it six when he blasted into the roof of the net with his left foot following a City breakaway.
That proved to be the final goal of a simple win for City, and here’s how we rated the players…
Manchester City player ratings
Had one major save to make when he held Gibbs-White’s strike, while the goalkeeper did rush out to make a hurried clearance at one stage. But overall, it was a quiet night for Ederson.
Kyle Walker- 6
Tucked inside and gave City an extra option centrally. He was also quick to drop on the rare occasion Forest launched an attack.
John Stones- 8 (off 75)
Used the ball excellently from centre-back and received repeated passes back from midfield. Stones also drove forward with the ball and demonstrated some neat turns.
Ruben Dias- 6
Didn’t have much to do and looked to get on the ball where possible and help his team attack.
Joao Cancelo- 7 (off 68)
Took his goal well and was a constant threat down the left flank. He provided real width in contrast to Walker from the opposite wing.
Rodri- 7 (off 54)
Saw a lot of the ball and kept it moving through the centre. The midfielder was rarely threatened by the Forest midfield and he was given a rare breather in the second half.
Ilkay Gundogan- 7
Never wasted a pass and was selective when to look for the ball in behind. Gundogan never looked rushed in possession, while also covering a significant distance on the night.
Julian Alvarez- 8
A superb display from the Argentine. Had it not been for Haaland’s hat-trick, Alvarez would have dominated the post-match discussion. The attacker played in the hole and distributed the ball well, while also dribbling effectively. A really promising showing from the summer arrival.
Bernardo Silva- 8
Silva was excellent again, cutting in from the right wing, especially in the early stages. He gave Lodi a torrid night and the No.20 looked composed throughout the game.
Erling Haaland- 9
Where to begin? The Premier League has unearthed a new legend. Haaland might not have had too many touches, but his ability to be in the right place at the right time is devastating. A man-of-the-match showing from Haaland who did drop deep on a few occasions, but habitually looked to sprint in behind the Forest backline. That’s nine league goals and counting for the Norwegian.
Phil Foden- 8 (off 54)
Did excellently for the opening two goals and was direct with his running down the left flank. Like Haaland, Foden repeatedly looked to run in behind.
Cole Palmer- 7 (on 54)
Did well after coming on and adapted seamlessly to the pace of the game. Palmer played off the left and linked well with team-mates.
Riyad Mhrez- 6 (on 54)
A quieter showing from the winger, although he did set up Alvarez’s first goal.
Sergio Gomez- 6 (on 68)
Drove down the left and looked a real threat for City. He also gave another indication of his technical ability.
Kevin De Bruyne- 7 (on 68)
Was very good in his brief cameo and looked to launch attacks behind Forest’s defence. It was his breakaway that led to the sixth goal.
Rico Lewis- 6 (on 75)
Didn’t have much time to make an impact, but put in a good tackle on Lewis O’Brien.
Nottingham Forest player ratings
Henderson 3; Williams 5, Worrall 3, Kouyate 4 (Biancone 78), McKenna 3, Lodi 4 (Toffolo 68; 5); Yates 4 (Colback 68; 5), Freuler 4, O’Brein 4; Gibbs-White 5 (Dennis 58; 5), Johnson 4 (Awoniyi 58; 4)