Den Ouden made his debut for Valletta in the first qualifying round of the Europa League against Icelandic side Keflavik, scoring a goal in the 72nd minute, to round the match to a 3–0 win for the Maltese side.
Valletta's Den Ouden entered the competition by playing in the first qualifying round of the Europa League against Keflavik from Iceland. He scored a goal in the 72nd minute, helping his team secure a 3-0 win over the Icelandic side.