The Norwegian has increased his remarkable goal tally in the 2022-23 campaign to 39 after just 36 matches across all competitions, following his five-star performance at the Etihad Stadium.
Haaland has now become the club's all-time record goalscorer in a single season, breaking a 94-year record held by Tommy Johnson who scored 38 goals in the 1928-29 campaign.
City's No.9 has also etched his name into Champions League folklore after becoming just the third player in the competition's history to find the net five times in a single match after Luiz Adriano in October 2014 (for Shakhtar Donetsk against BATE Borisov) and Lionel Messi in March 2012 (for Barcelona against Bayer Leverkusen).
At the age of just 22 and 236 days, Haaland has also surpassed Kylian Mbappe (22 years and 352 days) as the youngest player to score 30 goals in Champions League history, and has reached the 30-goal landmark in the quickest time, doing so after just 25 matches and beating the previous record held by Ruud van Nistelrooy (34 games).
All five of Haaland's goals were netted before the hour mark, including a first-half hat-trick, but the Norwegian was unable to complete an unprecedented double hat-trick as Pep Guardiola opted to replace the striker in the 63rd minute.
Ilkay Gundogan and Kevin De Bruyne were also on the scoresheet to help Man City breeze into the Champions League quarter-finals with an 8-1 aggregate victory over Leipzig, with Haaland unsurprisingly taking away both the match ball and that Man of the Match award.
Speaking to reporters, via mancity.com, after an extraordinary night on the blue side of Manchester, Haaland said: "It's a big night. First of all to play in the Champions League, I'm proud to play in it. I love this competition as everyone knows. Five goals and to win 7-0 at home, I'm so happy.
"I'm a bit blurry in my head so I don't remember them all, I was just shooting! I was so tired as well after the celebrations.
"I think after scoring five goals, I have to say scoring goals [is my biggest strength]. A lot of goals today I did not think, I was just doing it.
"Same with every goal, I didn't think. A lot of it is being quick in the mind and putting it where the keeper is not. A lot of it is in the head I think.
"I told him [Pep Guardiola] when I went off, I'd love to score a double hat-trick - but what can I do!"
Guardiola heaped praise on Haaland and the entire City team for their dominant showing against Leipzig, telling BT Sport: "It was a really good performance from minute one until the end from everyone.
"We play very good with and without the ball. We scored a lot of goals. Erling was amazing but everyone was exceptional. Five in 60 minutes. Incredible guy, huge talent. Power, mentality, he's a serial winner. Really good."
Meanwhile, Leipzig manager Marco Rose and defender Benjamin Henrichs have acknowledged Haaland's strength and hunger in front of goal following a "brutal" defeat at the Etihad.
"I know Erling very well, I know his qualities. When Erling is close to the goal, he wants to grab one. He scored four - no, even five tonight," Rose told reporters. "He has a great night. He was so hungry.
"He scored goals with the foot and head, won second balls, deep runs. It looked really simple. He took the ball from the referee, that tells you it was special night for him. Congratulations to Erling."
Henrichs - who was harshly adjudged to have handled the ball which led to Haaland breaking the deadlock from the penalty spot - added: "I have never before lost 7-0 in my career. It's a brutal and bitter evening for us. Haaland is physically very strong. He has a lot to offer; it is very difficult to defend him."
Man City will discover their Champions League quarter-final opponents on Friday morning before preparing for Saturday evening's FA Cup last-eight tie at home against Vincent Kompany's Burnley.