Erling Braut Haland of RB Leipzig celebrates after scoring his team's second goal with team mates during the UEFA Champions League group E match between RB Salzburg and KRC Genk at Red Bull Arena on September 17, 2019 in Salzburg, Austria.
Hwang Hee-Chan, Domink Szoboszlai and Andreas Ulmer also all got on the scoresheet for the hosts.
Haaland, who is the son of former Leeds and Manchester City player Alf-Inge Haaland, is the third-youngest player to score a Champions League hat trick after Raul in 1995 and Wayne Rooney in 2004.
BARCA DRAW, AJAX CRUISE PAST LILLE
Borussia Dortmund hit the woodwork and had a penalty saved before drawing 0-0 with Barcelona in their Champions League Group F opener on Tuesday, with Lionel Messi making his first appearance of the season for the Spaniards.
Barca's in-form 16-year-old Ansu Fati became the club's youngest player to feature in a UEFA competition when he started but failed to make any real impact before being replaced by fit-again Messi just before the hour mark.
Ajax gave a powerful reminder of their Champions League potential with a resounding 3-0 win over Lille in Amsterdam on Tuesday at the start of the group phase.
Last season’s surprise package look hellbent on a repeat of their heroics, which got them all the way from the preliminary rounds to the semi-finals, and goals from Quincy Promes, Edson Alvarez and Nicolas Tagliafico ensured an emphatic start to Group H.
RB Leipzig forward Timo Werner scored two second-half goals to secure an impressive 2-1 win at Benfica in their opening Champions League Group D match on Tuesday.