Louis van Gaal came through his latest perilous test with flying colors against Midtjylland on Thursday to keep one avenue open to a priceless place in the Champions League for Manchester United. A defeat on Sunday against Arsenal at Old Trafford, though, and another could effectively close off.

Van Gaal’s team will go into the fixture six points adrift of the Champions League places with just 12 points remaining. A defeat on Sunday and fourth-placed Manchester City would have a chance to extend that gap to nine points when they get round to playing their game in hand against Newcastle United. It would surely be too large to bridge and leave Manchester United relying on winning the Europa League and first of all getting through a just-drawn mouthwatering Round of 16 tie with Liverpool.

Should the door shut on Manchester United’s prospects of reaching the Champions League, the curtain could well come down on Van Gaal’s reign, just as happened with his predecessor David Moyes two years ago.

For just a couple of days, though, Van Gaal can enjoy some rare contentment in this tumultuous season. It looked as if the end was near when, already down 2-1 from the first leg of their Europa League last 32 tie, Danish champions Midtjylland took the lead in the return match at Old Trafford. Instead, his team put in one of their finest performances of his 19-month reign to run away emphatic 5-1 winners on the night.

Van Gaal could point, too, to a fairytale debut from an 18-year-old who grew up in Manchester as a United supporter. Marcus Rashford’s two goals provided the type of story that fans lap up, perhaps even enough to, temporarily at least, take some of the heat off of Van Gaal.

Yet taking a step back, there will be massive disappointment around Old Trafford that Sunday’s matchup is not a battle for the title. While United are 12 points adrift of top spot and have to work cut out just to reach the top four, Arsenal have their sights firmly set on landing the big prize for the first time in 12 years.

Arsene Wenger has landed the championship three times in England, with two of those resulting from pivotal victories at Old Trafford. In 1998 it was a 1-0 victory at Manchester United that prompted a sensational surge toward the title, while in 2002 a win by the same scoreline ensured the trophy would be heading to Arsenal.

“We are in a strong position in the league, that’s for sure, but there’s still a long way to go,” Wenger said on Friday. “Winning at Old Trafford in 1998 put us on a good run, but the second time [in 2002] we knew that if we won there we would become champions. It was a decisive game which is not the case on Sunday.”

Arsenal secured a dramatic win over Leicester City in their last Premier League outing two weeks ago to move within two points of the surprise leaders. In contrast to United, though, they have endured a tough time in the past week. A goalless draw at home to Championship side Hull City in the FA Cup fifth round was followed up by a 2-0 loss at the Emirates Stadium to Barcelona in the first leg of their Champions League last 16 contest.

The defeat was accompanied by an injury to Alex Oxlade-Chamberlain that will rule him out of the fixture. Manchester United, meanwhile, will be sweating on the fitness of David de Gea, Chris Smalling and Anthony Martial, while Wayne Rooney, Antonio Valencia, Bastian Schweinsteiger, Ashley Young, Phil Jones and Luke Shaw remain sidelined.

Prediction: Despite a poor season, Manchester United’s record against the Premier League’s top clubs hasn’t been all that bad. And after events on Thursday, the atmosphere at Old Trafford on Sunday could well be as good as it has been in a long time. Together with Arsenal suffering a chastening night in the Champions League on Tuesday, United could come away with a point to halt the Gunners’ title challenge.

Predicted score: Manchester United 1-1 Arsenal