Jose Mourinho is convinced Zlatan Ibrahimovic will remain at Manchester United next season for what the Portuguese believes will probably be "the last of his career at the highest level".
Ibrahimovic joined United on a 12-month deal from Paris Saint-Germain at the end of the 2015-16 campaign, with an option for a further year.
Mourinho has already stated his intention to trigger the clause and extend the former Sweden captain's stay at Old Trafford, although he warned it may be the beginning of the end for the 35-year-old striker.
Speaking ahead of Saturday's home game with Watford, Mourinho told a news conference: "I don't need his contract to be signed. I'm totally convinced he is going to stay. He came with the intention of staying two years.
"The first year is probably not going as he thought in his mind as he is very ambitious but in the minds of everyone it is going against every expectation.
"He knows we are going to try again to improve next season and try to share with him in a fantastic way probably the last year of his career at the highest level so I am convinced that he is staying."
Ibrahimovic has made quite an impression at United, scoring 20 goals in 33 appearances in all competitions.
Mourinho added: "He has also adapted to the club, the situation. I don't see any problem with his family.
"I gave him the possibility of an extra day off to relax, or go back to Sweden, he never wants to. Everything is stable so I'm totally convinced he is going to stay."