- Cristiano Ronaldo (19' Pen, 23', 44')
Ronaldo, who has now scored seven goals in five appearances for Al Nassr since joining, netted in the 18th, 23rd and 44th minute to seal victory.
Al Nassr started the day knowing three points would take them top following Al Ittihad's goalless draw against Al Raed on Thursday.
Ronaldo opened the scoring from the penalty spot following a handball from Damac captain Ibrahim Al-Nakhli.
Five minutes later Ronaldo doubled Al Nassr's advantage with a left-footed shot at the end of a swift counter-attack.
Abdulrahman Ghareeb's outside-of-the-foot pass was finished by Ronaldo a minute before half-time to complete his treble.
- Khalid Saleh Al-Turais