Ronaldo took just eight minutes to open the scoring at the Estadio Algarve as he finished from the penalty spot before doubling his tally soon after in the same fashion.

Bruno Fernandes netted a third inside a decisive opening 20 minutes before the Manchester United playmaker assisted Joao Palhinha for the fourth in the second half.

Ronaldo then secured his hat-trick with three minutes remaining to cap the host's dominant performance and ensure it remains a point behind Group A leader Serbia – which has played a game more – ahead of the next international break.

Sebastien Thill and Anthony Moris were the guilty parties for the early penalties with fouls on Bernardo Silva and Ronaldo, the latter clinically converting both.

Things went from bad to worse for the visitors as Fernandes made it 3-0 despite Moris getting a hand to his right-footed drive following Silva's throughball after 17 minutes.

Ronaldo almost claimed his hat-trick on the stroke of half-time but was denied by Moris, who also saved Silva's acrobatic volley.

Danel Sinani brought a rare save from Rui Patricio, with both Palhinha and Fernandes missing the target at the other end after being found by Nuno Mendes' searching deliveries.

Ronaldo's overhead-kick deserved to complete his treble, but Moris tipped over before Palhinha headed home from Fernandes' resulting corner.

Luxembourg almost grabbed a consolation goal through Gerson Rodrigues, but his left-footed strike was turned away by Patricio and Ronaldo completed the scoring as he headed in from Ruben Neves' deep cross.