After a dominant start on the back of four straight competitive wins, City deservedly took the lead in the 22nd minute, when Haaland coolly converted from the spot after Benjamin Henrichs was penalised for handball in the box.
Leipzig’s uphill task then got all the more difficult just two minutes later, as Kevin De Bruyne’s thunderous long-range effort crashed off the bar and straight to Haaland, who gleefully nodded home to strengthen the hosts' grip on the tie.
With half-time approaching, City went in pursuit of another goal to put the match beyond doubt.
Janis Blaswich thought he’d done enough to prevent further damage to the scoreline with a pair of superb saves to deny Erling Haaland and İlkay Gündoğan, but City’s Norwegian talisman bundled in a third with the final kick of the half to clinch his treble and give the hosts an unassailable advantage.
With the Cityzens boasting a three-goal cushion, few would have criticised Pep Guardiola’s men for taking their foot off the gas. But that isn’t in City’s playbook with their much-proclaimed 'cheat code' in attack, and the hosts came firing out the blocks in the second half, adding a further three goals before the hour mark.
The first of those saw Gündoğan finish a brilliant team move with a driven effort into the far corner.
Not to be upstaged by anyone, Haaland scored his fourth and fifth goals of the evening shortly after, with a pair of trademark predatory strikes inside the box.
With one eye on his side’s FA Cup quarter-final clash with Burnley at the weekend, Pep Guardiola soon replaced Haaland, as City looked to ease through the final 20 minutes against a Leipzig team comfortably beaten by the English champions of the day for a second time in three Champions League campaigns.
Even without Haaland up front, City weren’t done yet, and imposed further suffering on their flattened visitors with almost the final kick.
As the clock ticked past 90 minutes, the brilliant De Bruyne added late icing to the cake with a sensational long-range goal, as City extended their winning streak on home soil against German opponents in UEFA competitions to 10 matches in truly merciless style.
Flashscore Man of the Match: Erling Haaland (Manchester City)
