Former Town forward Daryl Murphy equalised on the hour for the Magpies after Freddie Sears’ first half opener at Portman Road, but further strikes from David McGoldrick and Emyr Huws won it for Mick McCathy’s men.
United face Preston North End at St. James’ Park next Monday in the first of their final three fixtures of the campaign.
And Ghanaian winger Atsu says Newcastle must “keep fighting” to make sure they’ll have something to celebrate come May.
“It’s frustrating, because before today we’d played really well against Leeds before we conceded that last-minute goal. But we cannot blame anyone, we just have to blame ourselves, correct our mistakes and continue working hard for the future,” he told nufc.co.uk.
“We’re really disappointed we lost this game, but we have three more games to play, we are still in a good position, and we have to keep fighting until the end.
“We didn’t start well, and we gave them confidence. We were not compact. But we have three more games to play and something to fight for, so we have to keep on doing that.”
Atsu added: “No one is happy with today. Everyone is down, but we cannot keep on like this – we have to make sure we change everything with our next game.
“We have to give more, fight, and just give everything in our next game, which is more important now.”
Two of Rafa Benitez’s side’s final three games are at home – something on-loan Chelsea man Atsu hopes, like the fact United have a week to refresh and prepare for the visit of North End next week, will help Newcastle in the run-in.
“It’s always great to play at home,” he said. “But in football, playing home or away is not necessarily an advantage, you just need to keep fighting and concentrate on our game plan. I hope and I believe that at the end of the season we will make our fans happy.
“We know the kind of position we are in now, and we know we cannot lose any games. We just have to keep working hard.
“We will have some rest and then the lads who have played a lot of games will have a good recovery, and we will come back strongly again.”