As Louis van Gaal spoke of wanting to “continue to the end” at Manchester United following another week when his job security was under intense scrutiny, Old Trafford’s embattled manager resembled anything but a man who potentially faces a date with destiny against Derby County tonight.

The Dutchman is not the first United manager to go into an FA Cup tie in the East Midlands with his future on the line. Only time will tell, however, whether Van Gaal will oversee a repeat of Sir Alex Ferguson’s Mark Robins-inspired escape act, at the other end of the A52 against Nottingham Forest in January 1990, when United face Paul Clement’s team at the iPro Stadium.

With United winning just three of their last 13 games in all competitions, another setback against the Championship side would further test the faith of Ed Woodward, the club’s executive vice-chairman, and the 5,000 travelling supporters due to make the journey from Manchester.

Yet with Woodward so far standing firm behind the 64-year-old, Van Gaal insisted he could win back the faith of the supporters and emerge on the other side of the storm to see out the remaining 18 months of his contract.

“I have signed a three-year contract, it is a process, not one game and I want to continue until the end,” Van Gaal said yesterday. “If I was not willing to do that, I don’t think I would have started here one and a half years ago.

“It is fantastic to have the support of Ed Woodward and the owners, but that also gives you a lot of pressure. When the board has such confidence, the pressure is much higher than when they say it is the last game or something like that. When your confidence is not so high, you can fight against it and, when you fight, you can have a bigger motivation than when they support you. But I always fight.”

While Woodward and United’s owners, the Glazers, continue to back the former Ajax, Barcelona and Bayern Munich coach on the basis of the stability he has brought to the club behind the scenes, results and performances on the pitch have led to support draining away among the fans.

Van Gaal was subjected to the jeers of supporters following last Saturday’s 1-0 defeat against Southampton at Old Trafford and he admits that he must rebuild the trust of those fans who no longer believe in his approach.

“It is always like that when you lose a game, certainly in the last minute, that you are fed up,” Van Gaal said. “How we have played is not always the main issue because you can play badly and win. When that happens, you are not so fed up.

Manchester United 0 Southampton 1 player ratings Show all 23 1 /23 Manchester United 0 Southampton 1 player ratings Manchester United 0 Southampton 1 player ratings David de Gea Helpless to deal with Southampton's winning goal. 6 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Phil Jones Looked to spark attacks from the back. 6 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Chris Smalling Unable to build on a strong first half display. 6 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Daley Blind Returned to the team as part of a three-man defence and failed to convince. 5 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Michael Carrick Often required to help out his defence at the vital moment. 6 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Antonio Valencia Supplied some testing crosses from the right that his teammates failed to capitalise on. 6 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Juan Mata Looked as threatening as ever on the ball, his shooting left little to be desired. 7 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Wayne Rooney Dropped deep into midfield in order to make something happen without success. 6 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Luke Shaw Booed by the away supporters on his reunion with Southampton, he performed well before being replaced. 6 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Robin Van Persie Cut a frustrated figure, he was booked for a bad challenge before being substituted. 5 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Angel Di Maria United's danger-man was guilty of trying to do much before he was subbed. 6 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Fraser Forster Struggled with his kicking at times, but was reliable in dealing with United's crosses into the box. 7 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Nathaniel Clyne Displayed a willingness to get forward from the opening minute, and never stopped running. 8 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Jose Fonte A rock at the heart of the Southampton defence, even after the loss of his defensive partner. 9 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Toby Alderweireld Looked a dominant presence back in central defence until his early injury blow. 6 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Ryan Bertrand Showed great energy in standing up well to United's attacks down the right. 8 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Steven Davis Calm in possession, and kept Southampton ticking over in midfield. 7 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Victor Wanyama Lacked the composure of his teammates on the ball, but crucial to breaking up the opposition's attacks. 7 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Morgan Schneiderlin A classy performer in midfield, he was culpable of a few needless fouls in dangerous positions. 8 GETTY IMAGES Manchester United 0 Southampton 1 player ratings James Ward-Prowse Excellent passing and responsible for a number of dangerous set pieces. 8 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Graziano Pelle Worked hard and pressurised from the front. 7 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Eljero Elia Showed pace and eagerness on debut before his removal for Tadic. 6 GETTY IMAGES Manchester United 0 Southampton 1 player ratings Dusan Tadic Took his time coming on, but proved to be the match-winner with a cool finish. 8 GETTY IMAGES

“But it is your duty as a manager and a player to stand up again and do what you do because that is a professional attitude.

“The fans believe in me, or maybe had believed in me. We can fulfil their expectations, but I am now more dependent on belief than facts. The facts are that we not in the top four, the gap is bigger now, so the belief is not so easy to achieve.”

A catalogue of injuries –leaving United without eight senior players, five of them full-backs, for tonight’s fourth-round tie – has been cited by Van Gaal as a central factor in the team’s recent slump.

Despite his own wounded pride, Van Gaal insisted he has not offered to walk away from his job in recent weeks following the dismal run that has left the team five points adrift of fourth-placed Tottenham in the Premier League.

“I have not mentioned that, ever,” Van Gaal said. “It is awful and horrible that you can write it. This is the third time that I have been ‘sacked’ and I am still sitting here for you, but I have always faced this [scrutiny]. But when you lose, it is even worse