Louis van Gaal admitted for the first time that Manchester United's best hopes of securing Champions League football next season will come from winning the Europa League.
Speaking after the defeat to struggling Sunderland, the United manager conceded his side had underperformed at the Stadium of Light.
"You have to win we can only blame ourselves," he told BT Sport. "Sunderland have had more aggression and we could not cope with that aggression."
Asked directly if his team could still finish in the Premier League's top four, the Dutchman admitted that recent results have dampened any hopes of qualifying for the Champions League.
"It shall be very difficult now. We give five points away - Chelsea and here. It's too much."
With United travelling to Denmark for Thursday night's Europa League tie against Midtjylland, Van Gaal indicated for the first time that, although not a straightforward task, the competition may be the best hope United have of returning to the Champions League.
"I think after this match it's the best route but it's not so easy as a lot of very good teams are participating in this event," he said.
