Haaland opened the scoring in the 22nd minute when he converted a penalty awarded after VAR consultation.
Just a few minutes after, he scored again. De Bruyne sent a powerful shot onto the crossbar and Haaland chased the rebound off the bar and headed into the net. The Norway star's persistence in front of goal was rewarded in first-half stoppage time when he scored his hat-trick.
City's talismanic striker continued his red-hot form in the second half, scoring again in the 54th and 57th minutes, after putting two rebounds past Blaswich.
With his five goals against Leipzig, Haaland reached 33 goals scored in 25 Champions League matches. The City striker has reached that milestone in fewer games than any other player.
He is also the youngest player (22 years and 236 days) to score 33 Champions League goals.
With his goals for Leipzig, Haaland has now reached 10 in the Champions League this season and is now top of the goalscoring charts, overtaking Salah (eight goals).
