#2 Rene Meulensteen

They say when you work under the best in the business, you're on track to become one of the best yourself. But Rene Meulensteen, as we all know is yet to become the best in the world.
Having worked alongside Mike Phelan, as the assistant manager at Old Trafford during their most successful spell between 2007 and 2013 under legendary Sir Alex Ferguson, he had a good experience that prepared him for a full-fledged job as a manager in the PL. But he flopped in his first and only PL stint so far with Fulham.
He was sacked after 75 days in charge, with just four league wins to his name in 17 games.
#1 Les Reed

We have now reached the shortest managerial spell in the Premier League history, with Les Reed holding the ignominy of being the holder of the record with his 40-day reign at the one and only club he ever managed in his career, Charlton Athletic.
He became infamous in the media during his six-week spell as the manager of The Addicks, having earned catchy nicknames like Les Misérables.
At least he managed one victory in his stint, but still his spell is counted among the worst managerial appointments of all time in league's history.