Manchester City striker Erling Haaland continued his red hot goalscoring form but Norway's bid for Nations League promotion suffered a setback in Slovenia.
Haaland, 22, scored his sixth goal in five games in the 2022-23 Nations League for the Group B4 leaders.
But goals from Andraz Sporar and Benjamin Sesko turned the match in Slovenia's favour in the second half.
Serbia will have the chance to leapfrog Norway at the top of the table when they meet Sweden later on Saturday.
A victory for second-placed Serbia would put them ahead of Norway on goal difference before the two nations meet in their final group match on Tuesday.