Portuguese star and all-time top scorer Cristiano Ronaldo drew first blood in the ninth minute. Six minutes later, Joao Felix made it 2-0 at the Stade de Luxembourg.
Just three minutes later, Bernardo Silva scored another one for Portugal, then Ronaldo netted once more in the 31st minute and the first half ended 4-0.
Portuguese midfielder Otavio netted another one for his team, then Rafael Leao scored the sixth goal for Portugal in the 89th minute, four minutes after missing a penalty kick.
Ronaldo reached 832 goals to cement his top spot in the all-time top scorers list.
Portugal leads Group J with 6 points, while Luxembourg is fifth with 1 point in the group standings.
EURO 2024 Sunday Results:
Kazakhstan - Denmark: 3-2
England - Ukraine: 2-0
Slovenia - San Marino: 2-0
Liechtenstein - Iceland: 0-7
Malta-Italy: 0-2
Northern Ireland - Finland: 0-1
Slovakia - Bosnia and Herzegovina: 2-0
Luxembourg - Portugal: 0-6