The Red Devils defeated St Etienne 3-0 tonight to put one foot in the Round of 16 of the Europa League with Ibrahimovic scoring a hat-trick.
While United remain sixth on the Premier League table, some 12 points from leaders Chelsea, they still have the EFL Cup final, the FA Cup and the Europa League to play for which suggests to Zlatan that there is silverware on the horizon if they can continue their winning form.
He told BT Sport: "We are winning, but in a short time everything can change.
"It's important to keep working hard to get the wins we need and keep the confidence.
"Everything can change fast, but we are happy at the moment.
"This is the decisive moment for the season, the second half of the season decides what happens."
Asked if United can cope with four competitions, Ibra replied: "That's the objective.
"Look at the Premier League. There are four spots for the Champions League, and one team will become a champion.
"The rest may not win a trophy and we are in all four. We already won the Community Shield.
"So if we don't win the Premier League we will get some other trophies."