Jose Mourinho has insisted for several weeks that he sees continental success as the best route for his side into the 2017-18 Champions League.
That led him to make eight changes to his starting XI for a trip to Arsenal, with key men rested as the Red Devils slipped to a 2-0 defeat.
While their Premier League fate is no longer in their hands, they only hold a 1-0 lead in their Europa League semi-final clash with Celta Vigo, and Ince believes they are playing a dangerous game.
The former United midfielder told Paddy Power: “If United had beat Arsenal, they’d be on 68 points with a game in hand and in a really advantageous position to make the top four.
“Champions League would’ve been in touching distance. I can see they’re clearly going for the Europa League as the main target, but I think that’s naïve.
“If they’d put out a slightly stronger team last week, they’d be touching top four. Just imagine if they hadn’t let so many silly points drop earlier in the season.
“It’s a massive risk, but if Mourinho takes United to the final and they win, people will say he did the right thing.”
United have slipped to sixth in the Premier League table, with defeat to Arsenal ending a 25-game unbeaten run in the top-flight.
They can, however, book their place in a European final on Thursday by seeing off the threat posed by La Liga outfit Celta – with Marcus Rashford’s stunning free-kick on Spanish soil having handed them the advantage in that tie.