Unwanted Dutchman is now tasked with toppling Inter, the Champions League holders and Italy's last hope.
Van Gaal aiming to leave a legacy in his last season at Bayern Munich
The 2011 Champions League has become quite a dangerous tournament for head coaches.
Barely had Louis van Gaal overseen a 1-0 defeat, in Milan, of the reigning champions Inter in the first leg of the rerun of last year's final than he was informed that this season would be his last in charge of Bayern Munich, but that, yes, he could go about tidying up as best he could any unfinished business.
Meanwhile, Schalke's relationship with Felix Magath, their head coach, looks more and more strained, even though Magath has guided the club into the quarter-finals of Europe's principal club tournament.
Claudio Ranieri left Roma in between legs at the last-16 stage while Inter let Rafa Benitez go just after he qualified them for the knockout phase. Benitez had anticipated that his stint in charge would be short even before he led the team he had taken over from Jose Mourinho in July to the Club World Cup in Abu Dhabi in late December.
By New Year's Day, Benitez was unemployed. The matches against Bayern that his Inter players had begun to look forward to would be contested under a new coach, Leonardo.
There are notable precedents, apart from Benitez, of a club coach leaving his job after winning a senior continental prize.
Mourinho resigned from both Porto and from Inter hours after winning the Champions League.
Jupp Heynckes, the German being tipped to take over at Bayern in the summer, will remember winning the Champions League with Real Madrid in 1998. His reward for bringing Real their first European Cup since the 1960s was to be replaced.
Were Van Gaal a more reflective sort, he might consider the ironies of all this as he prepares to galvanise a group of players who know their longer-term future will be under a different boss. This is a notoriously tricky task for a manager, but one that, on Saturday, the Dutchman appeared to be enjoying.
"I have the feeling the players were working a bit for me," Van Gaal said after Bayern beat Hamburg 6-0.
Some players echoed that. "I have been part of a side who played a sort of football under Van Gaal that I have never experienced before at this club," said Bastian Schweinsteiger, the long-serving midfielder.
"We very nearly won a treble last season. Bayern have done very well out of Van Gaal."
Against Hamburg, with Arjen Robben rampant, Bayern played the sort of football Schweinsteiger was referring to. Van Gaal's trouble has been Bayern's failure to recreate that football often enough.
Hence, with the club fifth in the Bundesliga - Saturday's win allowed them to climb a place - the board lost faith in his ideas and patience with his autocratic style.
For their part, the men who run Bayern - like Karl-Heinz Rummenigge and Uli Hoeness - will have been as encouraged by the fact that Hamburg did not register a goal as by Robben's hat-trick.
Bayern have kept only three clean sheets in their last nine outings, and the blitz they survived in the first leg against Inter suggests they will be required to defend rigorously again tonight.
Nor is Leonardo so new to his job at Inter that he has the honeymooner's protection.
The first-leg loss against Bayern adds to a number of domestic slip-ups that have punctuated his reign, the latest of which saw Inter let a 1-0 lead turn into a draw against Brescia, a result that may have been worse had Julio Cesar not saved a last minute penalty.
At stake for Inter in Munich is the prize they waited 45 years to reclaim, the European Cup; at stake for Italian football - with Milan and Roma out - is a presence in the last eight of the competition: Serie A is already falling behind the Bundesliga in Uefa's hierarchy.
In that sense, Van Gaal's legacy is far-reaching. His aim is to make it reach still further.
11.45pm, Aljazeera Sport +1