Edwin van der Sar has told Manchester United what to expect from Erik ten Hag with brutal verdict

The butterfly effect is the idea that small, seemingly trivial events eventually result in something with much larger consequences.

When Marcel Keizer and his assistants, which included former Arsenal striker Dennis Bergkamp were sacked at Ajax on December 21, 2017, few would have imagined that decision would have ultimately affected Manchester United just under five years later.

That decision eventually would affect United and that's because Ajax appointed Utrecht boss Erik ten Hag as their new head coach seven days after Keizer was dismissed. It's highly unlikely that Ten Hag would have ever been appointed United boss without Keizer being sacked. Those chain of events in Amsterdam around Christmas in 2017 have resulted in larger consequences in Manchester.

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Ten Hag started at Ajax in January 2018 in difficult circumstances, as Edwin van der Sar explained following his appointment, with comments that could be used to describe United's predicament now. "We had a bad summer and a messy start to the season," Van der Sar said. "From a sporting point of view, European elimination [from the Champions League preliminaries] was the low point.

"Marc Overmars and I have frequently spoken in the months afterwards about the permanent volatility of the first team. We are not confident that we will achieve the level that we are striving for with Ajax in this way.''

Ten Hag has arrived at Old Trafford with the club in a volatile positon, just like he did at Ajax. Ten Hag inherited an underperforming Ajax side in January 2018 and he's just left the club after winning his third Dutch league title almost five years later.

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