Jude Bellingham became the first player to score in each of his first four Champions League appearances for Real Madrid as they saw off-spirited Napoli.
The England midfielder headed in David Alaba's cross in the 22nd minute to put the 14-time winners 2-1 ahead.
It was the 20-year-old's 15th goal in his 16th appearance for Los Blancos.
He also assisted the fourth goal for Joselu in added time as Real continued their perfect record in this season's Champions League with a 4-2 win.
Giovanni Simeone opened the scoring for the visitors in the ninth minute but Rodrygo's brilliant curling effort brought Real level two minutes later.
Bellingham then put the home side ahead but Andre-Frank Zambo Anguissa equalised for the Italian champions just after the restart with a powerful volley from a tight angle.
Teenage substitute Nico Paz, the son of former Argentina defender Pablo, scored the third for the hosts in the 84th minute before Bellingham brilliantly crossed with the outside of his right boot for former Newcastle United and Stoke City striker Joselu to tap in.
Real had already advanced to the last 16 as Group C winners after matchday four and, even though they lose in Spain, Napoli remain second, three points ahead of their final opponents in the group Sporting Braga.
- Brilliant Bellingham breaks another record
Bellingham scored 14 goals in an impressive return for Borussia Dortmund last season.
After a 103m euros (£88m) move to the Spanish giants in the summer, he has already beaten his club tally this campaign - in just 16 matches.
The midfielder again dictated play across the Santiago Bernabeu pitch and found the target after a late surging run into the box, directing a looping header over Napoli keeper Alex Meret.
He almost had an earlier assist too after his late cross was met by Antonio Rudiger but Meret did well to tip the effort over the bar.
The former Birmingham City player has scored in all but four of his matches for his new club.