Picture : Haaland just behind Messi.

Ranking for the best goal-scorers in a single UCL knockout round

Erling Haaland, scoring 5 goals in the Champions League 1/8 finals tie against Leipzig (all 5 in the second game), entered the list of top scorers in one knockout round in the history of tournament.
It was just the 4th time that a player scored 5+ goals in two legs of an elimination round.
Lionel Messi holds the record with 6 goals against Bayer in the round of 16 in 2012.

PlayerNationalityGoals  Club SeasonRoundGames
  TotalLeg 1Leg 2    
Lionel MessiArgentina615Barcelona2011-121/8Bayer Leverkusen 3-1, 7-1
Cristiano RonaldoPortugal523Real Madrid2016-171/4Bayern 2-1, 4-2
Josip IličićSlovenia514Atalanta2019-201/8Valencia 4-1, 4-3
Erling HaalandNorway505Manchester City2022-231/8RB Leipzig 1-1, 7-0