Rafa Benitez reacts to Newcastle's fourth successive defeat
Benitez's side suffered a fourth successive Premier League defeat this afternoon.
Watford ran out 3-0 winners at St James's Park thanks to strikes from Will Hughes and Andre Gray and an own goal from DeAndre Yedlin.
The result left the club in 13th place – and just four points clear of the relegation zone.
“We knew this would be a difficult game for us, because they have been playing well," said Benitez.
"We needed to be strong and solid, but we made a mistake and conceded the first goal. We responded quite well. We were pressing and created a few things, but the second goal changed everything.
"Then it became very difficult in the second half. We were chasing and they were able to catch us out."
Benitez – whose team were as high as sixth last month – says he knew this would be a "hard" campaign.
“We are a team that has to work very hard to get results,” said United's manager, whose side face West Bromwich Albion at The Hawthorns on Tuesday night.
“We have to be aware that we knew this could happen.
"We knew we could lose some games and we have to analyse a few things and see why things are not going so well.
"But we knew it would be hard. We are a team that will have to work extremely hard right up until the end of the season.
"But the supporters, the players and the media have to realise (that) we have to work harder and stay together. That's the only way.”
Meanwhile, Watford manager Marco Silva felt that his team should have scored more goals.
Silva said: "It was an important result and an important three points. I think we deserved to win three points.
"We had a lot of chances to score more goals. We created a lot of chances. We should have scored more during the match.
"We've won an away match against a good team."
Asked about speculation linking him to the Everton job, Silva said: "I don't want to talk about speculation."