Norway had hoped to maintain their unbeaten streak in the Nations League, but Austria took control of the game early on.
Marko Arnautovic scored twice, while Philipp Lienhart, Stefan Posch, and Michael Gregoritsch each added to Norway’s troubles in Linz.
Norway’s lone goal came from Alexander Sorloth in the 39th minute, but it served as little more than a consolation.
Haaland took to Instagram for his apology, saying: “Sorry everyone, this was far too bad on my part. In November, we go for six points.”
Despite being Norway’s captain for the match, the striker faced criticism for refusing to speak with the Norwegian press after the game.
Following the defeat, Haaland received support from his international team-mate Sander Berge despite being off it on the pitch.
The Fulham midfielder said: “He has every right to do that. You can feel the disappointment now.
“We are a team in there, we stand in ups and downs regardless. The most important thing is that we are united.”
The result marked Norway’s heaviest defeat since 2017, leaving them with much to reflect on as they look ahead to their upcoming matches.
