The prolific Norwegian scored the third of Man City's four in their dominant victory in Slovakia, latching on to Rico Lewis's through-ball before rounding the keeper with consummate ease and rolling his finish into an empty net.
The goal was Haaland's 11th in just nine matches across all competitions, and incredibly his 42nd Champions League goal in just his 41st appearance in the tournament.
That brings him level with Del Piero's tally, although he has reached it in 48 games fewer than it took the legendary former Italy international.
Next in his sights is Neymar's haul of 43 goals - the 17th-most in Champions League history - while the likes of Eusebio, Filippo Inzaghi, Mohamed Salah and Didier Drogba are all now within striking distance.
Elsewhere, there was also a brace for the competition's third-highest scorer of all time, with Robert Lewandowski netting twice in Barcelona's big win over Young Boys.
The Polish striker is now just four away from becoming only the third player, after Cristiano Ronaldo and Lionel Messi, to reach a century of European Cup or Champions League goals.
Here, Sports Mole rounds up every player to have scored 40 or more goals in the competition.
Who has scored the most goals in Champions League history?
1. Cristiano Ronaldo (Manchester United, Real Madrid, Juventus)
Goals: 140
Appearances: 183
Ratio: 0.77
2. Lionel Messi (Barcelona, Paris Saint-Germain)
Goals: 129
Appearances: 163
Ratio: 0.79
3. Robert Lewandowski (Borussia Dortmund, Bayern Munich, Barcelona)
Goals: 96
Appearances: 122
Ratio: 0.79
4. Karim Benzema (Lyon, Real Madrid)
Goals: 90
Appearances: 152
Ratio: 0.59
5. Raul (Real Madrid, Schalke 04)
Goals: 71
Appearances: 142
Ratio: 0.50
6. Ruud van Nistelrooy (PSV Eindhoven, Manchester United, Real Madrid)
Goals: 56
Appearances: 73
Ratio: 0.77
7. Thomas Muller (Bayern Munich)
Goals: 54
Appearances: 152
Ratio: 0.36
8. Thierry Henry (Monaco, Arsenal, Barcelona)
Goals: 50
Appearances: 112
Ratio: 0.45
9. Alfredo Di Stefano (Real Madrid)
Goals: 49
Appearances: 58
Ratio: 0.84
10. Kylian Mbappe (Monaco, Paris Saint-Germain, Real Madrid)
Goals: 49
Appearances: 74
Ratio: 0.66
11. Andriy Shevchenko (Dynamo Kiev, AC Milan, Chelsea)
Goals: 48
Appearances: 100
Ratio: 0.48
12. Zlatan Ibrahimovic (Ajax, Juventus, Inter Milan, Barcelona, AC Milan, Paris Saint-Germain)
Goals: 48
Appearances: 124
Ratio: 0.39
13. Eusebio (Benfica)
Goals: 46
Appearances: 65
Ratio: 0.71
14. Filippo Inzaghi (Juventus, AC Milan)
Goals: 46
Appearances: 81
Ratio: 0.57
15. Mohamed Salah (Basel, Roma, Liverpool)
Goals: 44
Appearances: 80
Ratio: 0.55
16. Didier Drogba (Marseille, Chelsea, Galatasaray)
Goals: 44
Appearances: 92
Ratio: 0.48
17. Neymar (Barcelona, Paris Saint-Germain)
Goals: 43
Appearances: 81
Ratio: 0.53
18. Erling Haaland (Red Bull Salzburg, Borussia Dortmund, Manchester City)
Goals: 42
Appearances: 41
Ratio: 1.02
19. Alessandro Del Piero (Juventus)
Goals: 42
Appearances: 89
Ratio: 0.47
20. Sergio Aguero (Atletico Madrid, Manchester City)
Goals: 41
Appearances: 79
Ratio: 0.52