3 biggest mistakes from Van Gaal's tenure at Old Trafford

The revolving door at Manchester United has spat out its second manager in as many years.

It's a feature of the modern game that was once foreign to supporters of the Red Devils but is now a seemingly regular occurrence at the club which employed Sir Alex Ferguson for more than a quarter of a century.

With Louis Van Gaal's two-year tenure at Manchester United officially over, there's no shortage of moments to choose from that led to his dismissal at Old Trafford.

In what was supposed to be a time for Van Gaal to celebrate his first piece of silverware since taking charge in 2014, Manchester United's FA Cup triumph was immediately overshadowed by rampant reports that the team would part ways with the Dutch manager and replace him with Jose Mourinho.

His downfall as United gaffer resembled David Moyes' final months in charge at United as the atmosphere at Old Trafford became toxic after results on the pitch ultimately saw the team fail to qualify for next season's Champions League.

But which of the many mistakes since his arrival led to Van Gaal's failure to return United to prominence?

1. Abysmal transfer policy

The only praise Louis van Gaal deserves for the £250 million he spent in the transfer market arguably starts and ends with Anthony Martial. But even the French striker's arrival last summer has been overshadowed by reports of the massive transfer fee United have and will continue to pay for the talented 19-year-old.

One will find it hard to describe his overall dealings in the transfer market as anything other than an absolute disaster.

It all began with the Angel Di Maria debacle when the Argentine essentially begged for a move away by the time his debut season in England was over. He was eventually granted a move to Paris Saint-Germain - where he's returned to the elite form that warranted a his big-money move from Real Madrid to Manchester in 2014 - and paved the way for United to make another blunder with the signing of Memphis Depay.

Whether it was the acquisitions of Morgan Schneiderlin, an aging/ineffective Bastian Schweinsteiger, the supremely disappointing Radamel Falcao, or even allowing Javier "Chicharito" Hernandez to leave on loan to Germany, where he almost led the Bundesliga in scoring, Van Gaal can ultimately look back on his transfer policy as one of the primary reasons for two years of mediocrity.

2. Needless squabbling with media

Just about every post and pre-match meeting with the press became must-watch television in the second half of Van Gaal's season.

Every meltdown seemingly topped the previous week's outburst as the Dutchman grew increasingly frustrated with a line of questioning that often focused on his failures and reports of his impending sacking.

From pulling on a reporter's hair to portray a foul against Marouane Fellaini, to demanding an apology for reports predicting his firing at Christmas before storming out on reporters, Van Gaal has experienced more clashes with the press in two years than some manager's experience after decades with the British media.

Yet it was his first season in charge that produced one of the more memorable meetings with the press when he responded to Sunderland manager Sam Allardyce's remarks about United's style and how the team relied on the long-ball.

To prove his argument, Van Gaal took the feud to a new level when he prepared several charts for the press to prove that, in fact, Allardyce is a big old liar. Though it wasn't necessarily a conflict with the press, it was undoubtedly one of the most bizarre exchanges between a manager and reporters.

3. Champions League failure

Winning the FA Cup is nice and all, but missing out on a place in the Champions League this season will leave the most bitter taste in Van Gaal's mouth.

To his credit, he was successful in guiding United back to the game's most coveted competition with a fourth place finish in 2015. The club was finally back in the tournament that it once conquered on multiple occasions. But the experience was short lived when United bowed out after the group stage with a third place finish in a relatively weak group that included Wolfsburg, PSV Eindhoven and CSKA Moscow.

Meanwhile, a place in next season's Champions League slipped away in cruel fashion as United saw the last qualifying place go to hated rival Manchester City, despite finishing level on points.

It was a moment that surely left Van Gaal with his head in his hands, a gesture Untied fans became all too familiar with after an avalanche of disappointments that prevented the Dutchman from completing the three-year plan he set up for the Red Devils.