Al Nassr lost for the first time in 21 matches on Friday when Cristiano Ronaldo's side fell to a 3-0 defeat at Saudi Pro League title rivals Al-Hilal.
Former Lazio midfielder Sergej Milinkovic-Savic headed the league leaders in front in the 64th minute.
Aleksandar Mitrovic - who is Ronaldo's closet challenger for the Golden Boot - then added two late goals.
The scoreline was a little harsh on Al Nassr as the game had been a pretty even contest.
Ronaldo was denied a spectacular volleyed equalizer by a tight offside call when the score was still 1-0.
There were also suggestions that Mitrovic may have fouled Ronaldo in the build-up to scoring his first goal of the game.
Al-Hilal ended the game with 10 men after Ali Al-Bulayhi was sent off in added time for taunting Al Nassr supporters.
Friday's result takes Al-Hilal seven points clear at the top of the table.
Meanwhile, Mitrovic is now just two goals behind Ronaldo on the list of the top scorers in the SPL.
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