There is no such thing as a guaranteed success in football, but if Manchester United supporters are looking for reasons to be hopeful, they have a ready-made one: Louis van Gaal has won a league title with every club he has managed.
However, that little gem only tells half the story. It does not mention his first spell in charge of the Dutch national team and his failure to take them to the 2002 World Cup Finals.
Nor does it mention his second spell in charge of Barcelona, where he was sacked before the end of his first season, having lost nine of his 30 games.
Finally, it fails to take into account how breathtakingly awful Manchester United have been in the last year.
Be sure of this: Whatever van Gaal has achieved in the past, the future offers the biggest test of his abilities.
Van Gaal made his name at Ajax Amsterdam in the mid 1990s when he created one of the finest football teams in history.
With players such as Edwin van der Sar, the de Boer brothers, Edgar Davids, Patrick Kluivert, Nwankwo Kanu and Marc Overmars, Ajax dominated the Dutch league and lifted the Champions League in 1995 when they beat AC Milan 1-0 in Vienna.
His efforts in Holland were rewarded when he was given the Barcelona job in 1997 and again he led his team to success; winning back-to-back La Liga titles, leaving in 2000 after the Catalans were beaten to the championship by Deportivo la Coruna.
His two failures, with Holland and then his gruesome second spell with Barcelona, were followed by a renewal of his powers at AZ Alkmaar in Holland, where he would win the title in his fourth season.
He arrived at Bayern Munich in 2009 where he successfully cleared up the mess left behind by Juergen Klinsmann and promptly won the Bundesliga.
In 2010, only Jose Mourinho's Inter Milan could prevent him from winning the Champions League. Upon leaving Germany, he returned to the Dutch national team and lifted them to qualify for the 2014 World Cup Finals, which kicks off on June 12.
Of course, the irony is that van Gaal, for all his glittering success, may actually be perceived to be a diminished force by the end of next month.
Holland find themselves in a particularly tough World Cup group and have no guarantees of reaching the second round. With Spain and Chile to contend with, it's little wonder that van Gaal wanted to get the United deal signed and sealed before the World Cup began.
And what awaits him at Carrington?
A shattered squad littered with the remains of Sir Alex Ferguson's rusting big guns, a discredited bunch of youngsters, that big-haired folly of David Moyes and a perpetually disgruntled Wayne Rooney.
Those who suggested that Moyes was the sole problem at United were left to look a little foolish when even the appointment of Ryan Giggs failed to galvanise the misfiring players into anything even approaching their potential.