[8] That season, he experienced his breakthrough for the club under head coach David Nielsen, making 18 appearances – 17 as a starter – in the Superliga,[9] as AGF finished in third place and secured medals for the first time since 1997.

[10][11] At the same time as teammate Albert Grønbæk, Hausner signed another contract extension in mid-December 2020, valid until the end of 2025.

[12] He remained a starter in defense for most of the 2020–21 season, as AGF once again qualified for the championship round and finished in the top spots in the league table.

[13] On 20 May 2021, Hausner made a mistake that led to Mikael Uhre from Brøndby IF scoring the 2–1 winner, bringing the club one game away from their first league title in 16 years.

[20] He was criticised after the game by pundit Astrit Ajdarević, after failing to clear the ball which led to Norrköping's opening goal.

[21] His league debut following on 2 April, the first matchday of the season, again featuring in the starting lineup as Göteborg lost 1–0 at home to IFK Värnamo.

[24] On 24 August 2020, Hausner was called-up by Denmark under-21 national coach Albert Capellas for the squad for the 2021 UEFA European Under-21 Championship qualifiers against Ukraine and Northern Ireland.