United play host to the reigning Greek Super League champions, who hold a 2-0 lead from the first leg in the Champions League round of 16.
Despite that deficit, Moyes remains confident over his future, per Reuters, via Eurosport:
The biggest assurance is the club will let me get on with the job. I have a six-year contract. This club does not work on a short-term vision, it works on a long-term vision.
The support inside Old Trafford has been phenomenal. Sir Alex has been incredibly supportive, so has (director) David Gill and the board.
Sir Alex told me it was going to be a very difficult job but he is always there to help.
The Red Devils come into this week's fixture having just suffered a debilitating 3-0 loss at home to bitter rivals Liverpool, the first time since the 2008-09 season that the Merseysiders have managed a league double over their foes.
It's no secret that standards have dropped at Old Trafford since Ferguson's retirement at the end of the last campaign. United currently sit seventh in the Premier League table, were knocked out of the FA Cup in January and suffered a League Cup semi-final defeat at the hands of Sunderland.
Despite the nightmarish obstacles emerging at the Theatre of Dreams, though, Moyes remains adamant his side will rise to once again have their day in the sun, with him as their leading figure:
It has not been the season we wanted but I have ideas I want to put in place and the most important thing is Olympiakos.
If we can go through it would be a massive lift. We know we have got ourselves in a poor position being 2-0 down. [...]
The first thing I mentioned to the players is we need to start giving something back. We need to work together to make it a night to be remembered. We will leave nothing behind.
Moyes' level of success as United manager hasn't been impressive when compared to that of Ferguson, admittedly, but it's difficult to gauge whether any other tactician would have had a more fruitful time after replacing such an influential figure.
The BBC's Ben Smith points out exactly how Moyes' maiden campaign in the role compares to his job at Everton a year ago:
This time last season, David Moyes' Everton had 48 points from 29 games, having scored 46 goals & conceded 35— Ben Smith (@BenSmithBBC) March 18, 2014
This season, David Moyes' #MUFC side have 48pts from 29 games, having scored 46 goals and conceded 34 ...— Ben Smith (@BenSmithBBC) March 18, 2014
It's safe to assume that failure to qualify for the Champions League quarter-finals—especially considering that Olympiakos were seen as something of a fortunate draw—would be a major blow for the club.
Wednesday evening stands as another make-or-break moment for Moyes, an opportunity for United to either turn their fortunes around and begin to prove their critics wrong or creep further into the ever-growing shroud over this season.
Tough tests against West Ham and Manchester City come next, so Moyes may yet face further questions over his future across the next couple of weeks.