Four days after doing the same at Crystal Palace, the 22-year-old achieved a treble in the first half of 26 minutes to give Nottingham Forest a 6-0 win.
He is now the first player in the Premier League era to score nine goals in his first five appearances and is set to challenge Andy Cole and Alan Shearer’s record of 34 goals in a season.

Pep Guardiola believes Erling Haaland will become an all-time great at Etihad Stadium

Erling Haaland has scored nine goals in his first five appearances, a Premier League record.
Haaland has a long way to go to catch up with City record scorer Sergio Aguero, but Guardiola says the Norwegian can become a great club.
“Sergio is a great player. Nothing can break the hearts of City fans as the most important goalscorer in modern history,” he added.
“Erling has the quality of being. It’s not about him or Sergio. What Sergio has done is amazing. But Erling has this talent.
“When City bought Erling, everyone talked about what he has done in the past. All we wanted to do was help him. Hopefully he can enjoy and score more goals.
“What he has done in Norway, Austria and Germany, he tries to do it here. He is talented, we knew it.”

Norway scored a first-half hat-trick in Manchester City’s 6-0 win over Forest
Even at this early stage, it looks like only an injury will prevent him from claiming the Premier League Golden Boot, but Guardiola says winning the title with City will mean more.
“I think what we want is to win the title,” he said.
“If the record and the goal help us win that would be perfect. Knowing him a little bit, I don’t know if he would be happy to break the record if we didn’t win the title.
“I think he wants to be a part of it. The better we play, the more chances he has to score.”
It wasn’t just Haaland’s story as fellow new striker Julian Alvarez made his first league debut with a second-half brace.

Julian Alvarez is all smiles after scoring his first Premier League goals since his move to City
“Even Julian, we have two incredible strikers. An incredible sense of smell to score goals,” Guardiola said.
“I think there is no person who is not happy with Julian’s two goals. We have seen about him from day one in training.”
City are trying to sign Borussia Dortmund defender Manuel Akanji ahead of Thursday’s transfer deadline, but Guardiola says the move is not complete.
“The club told me the deal is still not done, but we are going to try,” said the Spaniard.