Rafa Benitez said Newcastle United "lacked focus" against Watford.
Benitez's side suffered a 2-1 defeat at Vicarage Road this afternoon.
Newcastle went 2-0 down in the first half, and goalkeeper Martin Dubravka kept them in the game with a series of saves, including a penalty stop from Troy Deeney.
United were much better after the break, and a goal from Ayoze Perez gave them hope of a result.
"I'm very disappointed," said manager Benitez. "We didn't start the game with the concentration we expected.
"We made too many mistakes, and that's why we lost the game. The reaction in the second half was good.
"So, if we had done what we were expecting to do from the first minute, we would have had control. We had control during the second half, but we made too many mistakes in the first half.
"(It was a ) lack of focus at the beginning. The first mistake, and after maybe we were a little bit worried about their strikers and we were not defending as a team. Then we conceded a penalty that it wasn't, so it could have been even worse.
"But in the end we lost a game that maybe we could have got a point from the second half, when the reaction was quite positive."
Newcastle remain 10th in the Premier League with two games left to play.