David Moyes might have turned down the chance to take charge of Sunderland last July had he known there would be so little money to spend on players.

Martin Bain, the club’s chief executive, recently acknowledged that the manager would have “very limited” funds during next month’s transfer window as Ellis Short, the owner, attempts to reduce a £140m debt while keeping his £73m wage bill within Premier League remuneration cap rules.

“Managing Sunderland always had an appeal to me but, if I’d known about the financial situation, I’d have needed to look at it in a different way,” conceded Moyes, whose bottom-placed team are at home to Watford on Saturday. “I’d have had to have thought a lot more about taking the job. I didn’t see us having no money in January. I’m disappointed I won’t be able to do some work in January and build on what we’ve done so far.”

When Moyes succeeded Sam Allardyce, he remained unaware Short was willing to sell Sunderland in the near future. “It’s a bigger challenge than I thought because of the situation the club are in and the situation I’ve been put in,” said the former Everton, Manchester United and Real Sociedad manager. “It’s a bigger job than I expected. I didn’t know the club could be going up for sale. I wasn’t made aware of it before.

“That would probably be what I’d say is the difficulty. I knew what we were spending in the summer was small in comparison to other clubs – and I said that to the owner but I didn’t see us having no money now. I hoped we’d get things done in January but that has shown itself not to be the case. But I’m going to move on. I’ve dealt with it in my head and we’re getting on with it.”

Moyes’s downbeat comments make quite a contrast to his optimistic message to Sunderland’s website on taking charge five months ago. “Martin Bain and Ellis have been terrific,” he enthused at the time. “They’ve given me some guarantees and reassurances about what we can do because we’ve got a big club here that we need to take forward. Celebrating staying up can’t be the goal. I’ve been really impressed by the owner and his guarantees to make sure that we keep improving.”

What particularly puzzles the Scot now is that Short had seemed so delighted to finally recruit him after four failed previous attempts. “I find that difficult,” said Moyes. “When I joined I was saying I’ve come here to improve the club. I don’t want to be here and us be a team at the bottom. This club has the infrastructure, the stadium, incredible support, some of the biggest crowds in Europe. That’s the appeal of Sunderland. And I knew the owner had wanted me for a long time.”

Many managers in similar positions would be strongly tempted to quit but Moyes has resolved to battle on. “I’ve not been tempted to walk because I’ve seen some steel from the players, a belief in what we’re doing,” he said. “The players didn’t know anything about the club’s situation either and we need to give them a lift. There have been some shoots of improvement but now we need to get in a huddle and stick together.”

It does not help that an already injury-ravaged squad has now lost Jan Kirchhoff, a key midfielder, for some months with a serious knee injury but Moyes remains inspired by Bain’s unstinting support. “I’ve a lot of respect for the chief executive, who was big and brave enough to say it how it is to the supporters and everyone here,” he said.

He hopes to repay such honesty by creating something of a siege mentality. “We’ve got some serious injuries and we’re very short, particularly in central midfield, but we have to say: ‘Let’s pull together and give 100%,’” Moyes said. “Patch yourself up whether you’re injured or not and get out.Sometimes that can galvanise you.”

“There’s frustration and disappointment but I’m going to stand up, stick my chest out and get on with it. I’m going to fight and I expect everyone else at the club to do the same.”

Even so, there is recognition that, in the current context, survival would be comparable to winning a trophy. “Staying up would be a good achievement,” he said, with considerable understatement. “Other managers have done it here but my task might be slightly harder.”