In the 2005–06 season, Tiendalli appeared more often for FC Utrecht, featuring in the first seven league matches, until he was sent off for a professional foul in the 65th minute of a 3–1 win against Feyenoord on 2 October 2005. After serving a one-match suspension, he returned to the starting line-up against SC Heerenveen on 23 October 2005, as the club drew 1–1. On 27 November he scored his first goal of the season, in a 1–0 win against Ajax. His second goal of the season came in a 3–2 victory over ADO Den Haag on 15 January 2006. Despite being sidelined during the 2005–06 season, Tiendalli continued to remain involved in the first team, making twenty-nine appearances, scoring twice, in all competitions.