The Manchester United managerial circus pitches its tent in Derby on Friday night for an FA Cup fourth round tie that Louis van Gaal recognises could undermine his position, even though he has just received the backing of the club's board to carry on in the job.

With a top-four finish looking more improbable with every passing week the FA Cup represents United’s only realistic chance of domestic silverware this season and, despite the competition’s devalued currency in the Champions League era, it is an opportunity Van Gaal would be keen to grab with both hands. “We want to win the FA Cup like everyone else in England,” he said. “It is popular, important and of course it is another title.”

Actually the FA Cup is no longer the first two of those things and in this country it has never been referred to as a title. Van Gaal would dearly love to win it, though, as it would allow him to continue with his personal narrative of having won titles in every country in which he has worked. At the moment his chances of winning a real title in England look slim, not because his team are faltering on the pitch – although they most certainly are – but because his stated aim of seeing out his three-year contract at the club is being jeopardised by crises of confidence on an almost weekly basis. Were United striding ahead in the league, they could cope with being knocked out of the Cup by a Championship club without too much heartache – teams striving for success in the Champions League tend not to be too bothered about the FA Cup.

Even though Sir Alex Ferguson's managerial career in England was saved by a Wembley triumph in 1990, a couple of decades later he could be found fielding weakened teams in semi-finals because his main interests lay elsewhere. But United are not striding ahead in the league. They are out of this season's Champions League and facing a struggle to get into next season's event. A poor result at the iPro Stadium would round off another bad week and force Ed Woodward, United's executive vice-chairman, to take stock once again of his manager's position – mainly because, with every setback, Woodward takes an equal amount of criticism as his beleaguered employee and, unlike Van Gaal, the top man at United hopes to be around for longer than three years.

Woodward seems to be pinning his hopes on Van Gaal's previous achievements and what might be termed the United template of showing patience and loyalty to managers who find themselves under pressure, in the hope they win through in the end and stay for 20 or more trophy-laden years. David Moyes does probably not think much of the United template and Van Gaal is not going to stay that long either, but cutting his losses does not seem to have occurred to Woodward, who has just sent out assurances that the Dutchman's job is safe for the time being.

Remarkably Van Gaal even seems ambivalent about that, although he may just be wary of the dreaded vote of confidence. “Of course it is fantastic to have Ed Woodward’s backing,” he said. “But when the board have such confidence in you the pressure is much higher than if they say it is your last game. Obviously I am happy with the support of Ed Woodward and the Glazer family, because I have worked for clubs who have not supported me and that is difficult. I always talk to the owners or the CEO before I join a club and I always have faith in people but to be encouraged to continue gives more pressure because now the fans have belief in me.”

It is hard to work out whether that is an unduly pessimistic view of the current situation or an overly optimistic one, though safe to say that, if there are any fans who retain belief in Van Gaal and his methods, their patience is unlikely to extend beyond another poor performance, be it in the FA Cup on Friday night or at home against Stoke in the league on Tuesday. Van Gaal’s United have often been accused of paralysis on the pitch, a disinclination to go forward and impose themselves on opponents, and their season is in danger of turning into a version of the same thing. Even if United win handsomely at Derby, the pressure will simply move on to the next game and will continue to do so until the side can put two or three convincing performances together.

That might not sound too difficult but Van Gaal has been unable to manage it this season and, if another Old Trafford first half passes without a United goal in the Stoke match, it will be 12 in a row. It can only be a matter of time before Manchester City supporters rig up some sort of totaliser to poke fun at this new phenomenon, like the one the Stretford End used to have to mock their rivals’ trophyless years.

It would not be the greatest surprise, in fact, to see some sort of public demonstration at Old Trafford itself should the sequence continue.

“We have fallen out of the top four but you have to look at the circumstances,” Van Gaal said in mitigation. “We have lost eight players to injury and five or six of them are contact injuries which will not clear quickly. I think people are a little quick to forget that we have been first in the Premier League this season.

“It is possible to get back into the top four but it depends how quickly players return from injury. I would still like to fulfil the expectations of the fans and the board – we are only half way through the season – but the fact is we are not in the top four any longer and the gap is growing. In those circumstances it is not so easy to retain belief.”

(Guardian service)