Newcastle's players are lacking belief admitted United manager Steve McClaren after Saturday's 2-1 defeat by Watford.
The Magpies are yet to win a Premier League game under McClaren and are 19th with two points from six games - they have won three of 25 games in 2015.
"No-one said this job was going to be easy, we didn't think it would be," said the former England and Derby boss.
"I am trying to change a lot and being here two and a half months, it's very difficult to change things quickly."
McClaren oversaw a slump at promotion-chasing Derby last season in the Championship and has won only two of his last 19 league games at the Rams and Newcastle.
But having been appointed in June, the 54-year-old said he had discovered more about his squad in the last week following defeat by West Ham last Monday.
"Certainly, it involves hard work and sticking together and keeping calm and that is what we have to do," he said. "It is a long season, and we have come in and in the last week learned a lot about our team.
"There are a lot of things - mentality, getting a bit more belief, so there are things to work on. Things we knew before and now have just been confirmed. We will lick our wounds and work hard on the training field as normal."
McClaren believes in players
Despite BBC pundit Garth Crooks claiming McClaren "could be out of a job by Christmas" if their form remained the same, the Magpies boss said: "There is history that needs changing and turning around, give it time.
"I believe in that squad of players and we need to fight. I think we did that in the second half, and nearly got back in the game."
"We thought the last two games would be a test for us and we would know a lot more and we know now this is a tough job."
Magpies leave Shearer far from impressed
Newcastle went behind to two Odion Ighalo goals as last season's Championship runners-up established control at St James' Park, where Newcastle have won twice this calendar year.
Daryl Janmaat's second-half goal gave encouragement to the home supporters, but they were left without any reward with Newcastle only scoring three goals in six matches this season.
Former Newcastle striker and manager Alan Shearer was unimpressed with what he saw on Saturday - and was clearly angry as he analysed their performance on Match of the Day.
"This is a Newcastle team that got battered by the media after they lost at West Ham on Monday. I thought they would go out today and have a right go. But no," said Shearer.
"Midfielder Flaurian Thauvin turned up at the ground in a tuxedo. That was funny at the start of the season but it isn't now. This is serious.
"It was far far too easy for Watford, who were brilliant but helped by Newcastle's defending. The lack of quality was alarming
"From start to finish Newcastle were abject and the manager has big problems."
Former Tottenham player Garth Crooks had earlier said on Final Score: "The more Watford go on and play the way they did today, the more they will gain belief. Newcastle lacked belief, ability and confidence, and McClaren is struggling to inject it.
"The way things are going, McClaren could be out of a job come Christmas. The expectation at St James' Park is sky-high. Can he match that expectation? I doubt it. The fans need to see something, effort at least."
Newcastle host champions Chelsea in their next Premier League game before travelling to top-of-the-table Manchester City.