Flekken grew up in Bocholtz, Limburg, Netherlands on the German border.[2] His parents René and Annie used to play football themselves, and his younger brother Roy also became a goalkeeper.[3]
Club career
Alemannia Aachen and Greuther Fürth
Flekken started his career in the youth department of RKVV WDZ from Bocholtz before moving to the youth academy of Roda JC Kerkrade. In 2009, he moved across the border to the youth teams of the then 2. Bundesliga club Alemannia Aachen. On 22 September 2011, he signed his first professional contract.[4]
During the winter break of the 2012–13 3. Liga season, Flekken was appointed as the starting goalkeeper by coach René van Eck after the financially troubled club had parted ways with Michael Melka.[5][2] Flekken made his debut on 26 January 2013 in a 2–0 home game against 1. FC Saarbrücken.[6]
Flekken signed for MSV Duisburg on 12 June 2016.[8] On 7 August 2016, he scored a goal, after a corner, in a 1–1 draw against VfL Osnabrück, when he went to the opposite box during the last minute.[9] In February 2018, Flekken conceded a goal in a 2. Bundesliga match against FC Ingolstadt, when he turned his back on the play to take a drink from his water bottle.[10][11]
Flekken started the 2021–22 season as the undisputed first-choice goalkeeper and, after ten games in a row without defeat, saw the team in third place of the league, to which he had contributed with the league's best rate of shots saved.[16]