Van Gaal, 64, is in a precarious position after United slumped to a 2-0 defeat at Stoke City on Saturday. It was a fourth successive loss and United have fallen to sixth in the table.
Chelsea are the Premier League champions but have showed dazzling incompetence in the defence of their title and hover just above the relegation zone.
Following United's latest setback, van Gaal suggested that he might walk away from the job rather than wait to be dismissed.
"I have said in former press conferences that it is not always for the club to fire or sack me. Sometimes I do it by myself.” Van Gaal was appointed in July 2014. His arrival came a year after Sir Alex Ferguson retired and the disastrous stewardship of his replacement, the former Everton boss David Moyes.
The goal was to steady United who had failed to qualify for the Uefa Champions League under Moyes and re-establish them as a title chasing team.
United are only six points behind surprise pacesetters Leicester City. But it’s the manner of their slump – three Premier League setbacks on the trot - that has raised doubts about van Gaal’s suitability to continue at the helm especially after he has overseen a spending spree of 200 million euros with the acquisition of the France internationals Anthony Martial and Morgan Schneiderlin, the Netherlands internationals Memphis Depay and Daley Blind as well the World Cup winning Germany skipper Bastian Schweinsteiger.
Van Gaal has the chance to redeem his reputation as an astute tactician and keep the wolves from the door with the game against Chelsea who are in a slough of despond. The Premier League champions lie a few points above the relegation zone after losing nine games of the camapign. Star players have underperformed to such an extent that manager Jose Mourinho was dismissed eight days ago.
His departure was followed by a 3-1 home win over Sunderland. But on Saturday, Chelsea needed a second half equaliser from Diego Costa to earn a point against Watford at Stamford Bridge. Chelsea might have even taken all three points had Oscar not missed an 80th minute penalty.
Hiddink, who acknowledged that United are going through a difficult time, says his players need to concentrate on their own form and to take the game to Untied. "We will go to Old Trafford, it will be difficult, but I hope this team will show, the ambition like they showed against Watford,” said the 69-year-old former Netherlands boss. “We are going there for the win."