With 18 points separating United from Premier League leaders Chelsea, Jose Mourinho's side are unlikely to win the league title.
Ibrahimovic has won 13 league titles in four different countries in the last 15 years.
Star strikers who could replace Zlatan Ibrahimovic Thu, April 13, 2017
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But he may have to settle with just the EFL Cup and potentially the Europa League.
And though the 35-year-old striker still thinks United have a slim chance in the league, he will view non-success in a dim light.
He told BT Sport: "Of five trophies we've won two. We have another two to play for. I think number one spot, I still believe even if it is mission impossible.
Manchester United's Zlatan Ibrahimovic
"In myself I hope. I work for that because that is my aim. Last time I came second, I don't even remember that, it was with Milan. Whatever comes after the first is a failure.
"But we still have other trophies to play for. So I think we are doing great because the team is what it is.
"We are doing the best we can and we still want more."
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