The ex-Chelsea manager claimed to be a huge ally to his former mentor but now he has helped to ensure that he takes the veteran Dutchman's job from under his feet
When Jose Mourinho was sacked by Chelsea for the second time, his agents couldn't have made it clearer that he was ready to jump straight back into work.
"He will not be taking a sabbatical, he isn't tired, he doesn't need it, he is very positive and is already looking forward," they said in a statement shortly after he was shown the door in December.
It just so happened that he wasn't the only high-profile Premier League manager struggling at the time. Having just overseen Manchester United's exit from the Champions League, Louis van Gaal was under pressure himself. Defeats by Bournemouth and Norwich City had also followed as a run of insipid performances cast doubt over the Dutchman's future at Old Trafford.
"Because of his love of football, you will see Jose at football grounds working and supporting friends," continued the statement. "He will not be attending any high-profile games because he wants to discourage any speculation about his future."
Once upon a time Van Gaal would have been one of those friends whom he would have been supporting. As high-profile as any Manchester United game is, he may well have been seen backing the man who gave him his big break in football.
"I consider him a big, big, big, big friend," Mourinho said of the Dutchman during the 2014-15 campaign, "but because we are working in the same country and our clubs have the same objectives, we are not speaking every week. But that feeling of him being a big friend doesn't change."
That friendship was cultivated back in the 1990s when Van Gaal turned Mourinho from a willing translator to a respected young coach of some distinction during their days together at Barcelona.
"Mourinho thought he'd been promised the youth academy job and even that he might be the next manager and hadn't been told," Van Gaal explained of his apprentice's attitude after the Dutchman had been handed the Barca job.
"He was so angry and shouted so much about not being consulted that I was impressed. On that day he was a Special One and because of that I hired him.
"I learned that day he was special. He was an excellent co-trainer, a substitute coach. Also, and I don't do it very often, I let him coach matches, because I was convinced he had specific qualities."
Van Gaal might now be left wishing that he hadn't bothered, with Mourinho about to be handed his Manchester United job after he was sacked on Monday following five long months of speculation fuelled by the Portuguese and his advisors.
Six days after Mourinho had been fired by Chelsea, Van Gaal walked out of a press conference having been visibly upset with rumours that he was about to be sacked and replaced by his former friend. No words of encouragement came from the Portuguese.
Two matches later, United had lost four games on the trot and not won in eight as they welcomed Chelsea to Old Trafford. On the forecourt at the Theatre of Dreams were street salesmen with Jose Mourinho United scarves but still the man himself did nothing to ease the pressure on his "big, big, big, big friend".
As pressure built on Van Gaal through the spring amid further defeats to the likes of Southampton, Midtjylland and Sunderland, the volume reports linking Mourinho with the 64-year-old's job only increased but, instead of moving to deflect speculation, the Special One and his team continue to lurk in the background.
While Manchester United could have handled the whole situation so much better, they were helped in no way by constant tip-offs by Mourinho's agent Jorge Mendes that something would happen sooner or later.
Reports broke that Mourinho would arrive at United within days, that he would be compensated to the tune of £15 million if he didn't eventually become the manager - £5m of it if he wasn't installed before the end of the season – and that he would somehow, sometime, replace Van Gaal come what may. Whatever the particulars, what was clear was that there was communication between Mourinho and United.
And not once did the Portuguese come out and categorically deny an interest. Not once did he put the feelings of his "big, big, big, big friend" before his need to stir the pot. He would instead find a photo opportunity after a United setback. He'd go for a stroll upon the sight of cameras just when he needed to keep his name in the frame. He didn't move to quell speculation, he encouraged it.
All the while, Van Gaal was struggling to keep his head above water. On the pitch, results were not justifying the stunted approach to attacking football with which he constantly sent out his team, while, off the pitch, reports on his impending dismissal were the flavour of the moment for every moment of every day for five long months.
Van Gaal had remained so convinced that he would stay in his job that he took on a cocky air with reporters in press conferences whenever they raised the issue. Every time he was questioned, his answer came in various shades of "I'm still standing".
"I don't discuss it with my friends of the media who have already sacked me for six months. Which manager can do that, what I have done?" he asked after winning the FA Cup on Saturday.
But those long, tedious months of football played against a backdrop of long and tedious speculation are now over. Mourinho's and Mendes's machinations have eventually worked to devastating effect.
Van Gaal is no longer standing proud in the face of speculation. He is no longer Manchester United manager. And it wouldn't be a surprise if he no longer considers Jose Mourinho a friend.