Considerable uncertainty surrounds the manager’s position at Sunderland after Dick Advocaat refused to confirm he will remain in charge beyond Saturday’s game at home to West Ham.

It is understood the Dutchman could well step down regardless of the result against Slaven Bilic’s side after becoming disillusioned with life on a limited budget at the Stadium of Light.

Despite maintaining he was still the “best man for the job” the normally affable 68-year-old became so vexed by questions regarding his future that he walked out of an abridged but contradictory pre-match media briefing on Friday.

Having deflected a series of questions from television reporters in increasingly opaque fashion, Advocaat rose from his seat and exited stage left less than two minutes into a subsequent chat with national newspaper reporters.

The tipping point was a request to clarify whether he intended still to be the club’s coach on Monday morning. “I will not give you an answer on whether I’ll be the manager, if I’m not then I will not be sitting here,” said Advocaat who described the question as “rude”.

Gus Poyet’s successor had previously said he would remain in situ as long as he felt he remained the best equipped coach for the job and on that score he maintained that nothing had changed. “I still think I’m the best one,” he said. Would this be regardless of what happened against West Ham, somebody asked. “Definitely,” he said before suddenly truncating the conversation and leaving the room.

Shortly afterwards Advocaat, whose side are bottom of the Premier League and have still to win a league game this season, declined a request from Sunderland’s press officer to return. In a matter of minutes his demeanour had shifted from reasonably relaxed to intensely irritated.

Earlier, in the part of the briefing for TV reporters, a man who has previously made plain his belief that Sunderland’s squad required greater investment this summer was, confusingly, rather more positive about his future on Wearside.

Asked if reports that defeat by Bilic’s side would prompt his resignation were true, the reply was unequivocal: “Definitely not. I don’t know where that has come from.” After that his answers quickly became increasingly opaque. Reminded that two weeks ago he had described himself as “a long way” from stepping down, Advocaat initially issued a firm response: “Nothing has changed.”

Then, sounding considerably less certain, he added: “When it is time to do something, then I will do so. Today is not the time to do something. For me it’s important to discuss what happens tomorrow, not to say what maybe will happen on Sunday or a week later. When I feel it’s the time to do something then I will do that.

“I always think in facts. The fact is it is now Friday and I am manager of Sunderland but what will happen on Sunday, or a week after Sunday, or nine months after Sunday – then I will tell you the real story. But now I am still here.”

By now the mood music was altering. “The fact is you can be ill tomorrow,” he said, once again body-swerving the afternoon’s central question. “The fact is I am here today and tomorrow I am here. But what happens after that – it is the same for all managers. Things can change in a day, in a week, in a month, in nine months.”

Whatever the repercussions, West Ham’s visit appears a potential watershed. “We have to use tomorrow as a cup final and get that result because if you win you get confidence – but it is very difficult to get that win,” Advocaat said. “We have to start getting results because, otherwise, we are going down. It’s very important to win tomorrow.”

In the wake of saving Sunderland from relegation last spring, Advocaat announced his retirement before being talked into a volte-face by Ellis Short, the club’s owner. He hinted that he might do another U-turn following the transfer window but resisted the temptation. A month on, though, he appears even more undecided about his future at a club which has sold around 43,000 tickets for Saturday’s fixture.

“You might not believe me but I still really like what I’m doing. This is a great club, the facilities and the stadium are great,” he said, somewhat wistfully, at one point. “The only thing missing are the results.”