On 23 March 2013, Mandous made his competitive debut in the second leg of the fourth round of the Czech Cup against Hradec Králové.

Mandous played 18 games in this campaign, which ended with the club being relegated to the third flight of Czech football.

Mandous joined Žilina as a free agent in June 2015, when he signed a two-year contract with the club.

[2] On 12 August 2015, he made his competitive debut in the Slovak Cup match against ŠK Strážske, which Žilina won 9–0.

Mandous played the full 90 minutes for Czech Republic against Scotland which ended in a 2–1 defeat for the home side.