David Moyes is coming under increasing scrutiny from the Manchester United hierarchy, though the manager insists that his situation remains the same.

When asked about his job security, before Wednesday's Champions League second leg against Olympiakos, Moyes said: "My future has not changed one bit. I have got a great job, I know exactly the direction I want it to go in. It's not been the season we hoped we would have but I have ideas of what I want to do and put in place when the time is right.

"The most important thing now is to get the Olympiakos game played and hopefully get through. If we can it would be a massive lift but we know we have got ourselves in a poor position being 2-0 down. We have got a lot of belief and we have got to try to make it show in the game."

Over the coming week Moyes faces the return leg with the Greek champions at Old Trafford on Wednesday and Saturday's trip to West Ham United before the derby at home to Manchester City the following Tuesday, three games which could prove critical to his hopes of holding on to the job.

The position of the owners, the Glazers, is that Moyes retains their support but a discernible shift in the mood within the higher echelons reflects a desire to see noticeable signs of improvement.

Despite the Glazers having no wish to remove him as manager, Moyes conceded he has not been given any guarantees. "The biggest assurance is that they let me get on with the job. We never discuss it, we talk about the future. We are making big plans for years going forward, this is why it's a six-year contract, this is not a club that works on a short-term vision, it works on a long-term vision."

In a dismal title defence United are 18 points behind Chelsea, and 12 from Manchester City in fourth place, with the 20-times champions seventh. The 3-0 humiliation by Liverpool at Old Trafford was viewed as particularly disappointing due to the manner of the defeat and the concession by Patrice Evra that United are not used to being in such a lowly position will have been noted. "It's been a difficult season for everyone because we are not used to losing games, we always win," the defender said. "It's a difficult moment. It's a new challenge because we have never been in this situation, we are always playing to win the league, to win games, to win the Champions League, it's tough moment and you have to show your character and personality."

Moyes has taken strength from the support of fans at Old Trafford. United have lost five times at home in the league this season – the last time they lost six home games was 36 years ago in the 1977-78 campaign.

Losing the backing of the United hardcore would cause further debate at board level regarding his position but when it was put to Moyes that supporters might not be able to stomach another abysmal display against Olympiakos he was again defiant. "I actually think they have seen some defeats they would not have expected and have stuck with the team throughout. I think they understand the period we're all in together."

Moyes admits that displays like the one against Liverpool cannot be repeated. "When you lose in the fashion we did and obviously to one of our biggest rivals there is always a lot of disappointment," he said.

"We knew it was a big week with Liverpool and Olympiakos but as soon as it was over we were concentrating on this game. We told the players that on Monday morning when we got them back in that the only thing that matters now is this game and our focus now is now on that."

Despite the sense that some players have not bought into his ideas and are not completely committed, Moyes is determined to back them, publicly at least. "I see the players every day, I have the chance to work with them every day, the qualities they show me," he said.

"I think they know they can play better, I don't think any of them are questioning that. I've got a belief in the players. I can see what they can do and hopefully they can show it. I agree they have not showed it as often as we'd like but we will try to make that happen on Wednesday night."