On 7 August 2016, Fellaini played the full 90 minutes in United's 2–1 Community Shield victory over Leicester City. On 4 December, he made his 100th appearance for United against his former club Everton and conceded a penalty just a few minutes after coming on as an 85th-minute substitute. Leighton Baines successfully converted the spot kick in the 89th minute to secure a late equaliser for the "Toffees" in a match that finished 1–1. Due to José Mourinho's preference for Ander Herrera alongside Paul Pogba in central midfield, Fellaini's appearances for Manchester United had become limited to coming off the bench; however, on 11 January – the day after he scored the second goal in Manchester United's 2–0 win over Hull City in the first leg of their 2016–17 EFL Cup semi-final – Manchester United activated a one-year extension clause in Fellaini's contract, keeping him at the club until the end of the 2017–18 season. The Belgian featured for the entirety of United's 2017 UEFA Europa League Final victory against Dutch club Ajax.