Manchester United face a wait for the Premier League title if rivals Manchester City continue to spend, according to manager Jose Mourinho.
United have not won the league since 2012-13 and Mourinho's side are already eighth and 18 points adrift of reigning champions City after 15 matches this season.
The Red Devils, who are winless in their past four Premier League matches, finished 19 points behind City last term and Mourinho warned the club's trophy drought could continue unless City's spending is reined in.
"I don't know," Mourinho said when asked how long it would be before United won the Premier League again.
"It depends on our evolution but also others' evolution. If the ones above us keep going in the same direction, and if their ambition and investment is continuous, that’s one thing.
"Another thing is if they stop, or if the Financial Fair Play makes them stop, and then we can close the gap a little bit better."
"The world is full of suggestions and I never know if they are true or not true, and that's not my job to analyse that," Mourinho added on the likelihood of City being punished.
Liverpool have not won a league title since 1990 and when asked if he could see United facing a similar drought, Mourinho replied: "I don't know what happened in Liverpool. I just know the numbers but I don't know why."
United, who played out an entertaining 2-2 draw with Arsenal on Wednesday, welcome lowly Fulham to Old Trafford on Saturday.