After Coutinho's departure, Liverpool went on to new heights. They made the final of the Champions League months after the Brazilian's exit and won Europe's biggest title a year later, conquering Barcelona along the way.
At the time of writing, they sit eight points clear at the top of the Premier League table after just eight games of the 2019/20 season.
Indeed, almost as soon as Liverpool reinvested the £142m transfer fee received from Coutinho's move in their uncertain defence, with the signings of Alisson and Virgil van Dijk, their one-time talisman became forgotten.
Meanwhile, for Coutinho his dream move to Camp Nou quickly became a nightmare, eventually leading to a loan move to Bayern Munich this summer. The expensive flop became even more irrelevant in England as Liverpool soared.
But should he be so easily erased from the minds of Liverpool supporters? Perhaps not. Perhaps the Reds should have sought the opportunity to reunite him with the Anfield turf.
It may feel impossible to criticise the current Premier League leaders and reigning European champions, but, if there is one area of the pitch in which they are weaker than some of their competitors, then it is definitely their midfield.
A sturdy, but relatively immobile, central three of Fabinho, Jordan Henderson and Georginio Wijnaldum has been enough for Liverpool so far, but with pressure rising on their title challenge, they seem to lack a little creativity in the middle of the park.
Liverpool have won all eight of their league games this campaign, an incredible record. But it has been far from convincing at times. They needed a 95th-minute penalty to avoid a draw at home to Leicester in their last match, as well as a howler from goalkeeper Dean Henderson the week before to squeeze past newly-promoted Sheffield United.
Whilst their full-backs and front three continue to provide devastating attacking displays, Liverpool's midfield has produced only two of their 20 Premier League goals this term. This lack of threat has the potential to leave Liverpool in a difficult situation come an off day for the attackers.
So who could fill that gap? Well, they would need someone who scores goals and provides them for others, a player who could fit in to Jürgen Klopp's system and a tried and tested Premier League star.
Tick, tick and tick.
Philippe Coutinho could just be the man for the job. He is a magician with the ball at his feet, operating in the tight spaces that deep-lying opposition defences create for Liverpool.
The Brazilian has the ability to carve open stubborn formations and boy can he hit a strike from outside the box. He already has two goals and three assists in only six starts for Bayern so far, and he is starting to show the form the Premier League was all too accustomed to. He has all the attributes required to succeed, again, at Anfield. But Liverpool fans already know that.
Put simply, Coutinho offers Liverpool something they don't have. That spark, that flair from the centre of the pitch. Liverpool have seen glimpses of such attributes from Naby Keïta and Alex Oxlade-Chamberlain, admittedly, all too briefly.
But injuries and form suggest that neither aforementioned midfielder can offer the consistency to aid Liverpool in their hunt for more silverware.
Liverpool's lack of summer signings caused concern for many supporters, with the Reds failing to make additions to their squad from a position of great strength. Maybe the one they needed, and once knew intimately, just slipped from their grasp.
Source : 90min