The signs were there, for those who can read the subtle language of Jurgen Klopp’s musings.
Speaking earlier in the season about a Porto side who his Liverpool team destroyed in both 2018 and 2018, he warned against lazy assumptions.
The Portuguese side, he said, were technical and inventive, with a real threat from pacy wide players who were intelligent and adaptable in their positional play and tactics. In hindsight, he was referring to Luis Diaz.
With those words, we can understand why Liverpool have made a swoop which has taken so many off guard - most notably Spurs - for a player who was barely on the football radar until last summer.
Back then, he took hold of the Copa America for his nation Colombia and almost made the tournament his alone. A spectacular overhead kick against Brazil in the group stages announced him as an audacious talent.
But a searing run and clever finish in the semi final to embarrass Argentina showed him as the perfect Klopp forward. As the perfect modern forward in fact.
He has work-rate to do his defensive and pressing duties, unselfishness to turn provider, but an instinct to get inside the far post and finish chances when the opportunity arises.
His 14 goals in taking Porto to the top of the table - the second top scorer in the league - show that instinct has continued this season. And yet it hasn’t changed his humble approach to football and to life.
His club captain Pepe spoke about the winger, saying he is “proud to share a locker room” with a player of such “professionalism and passion”. In Klopp’s adopted Scouse words, he is “a good lad”.
Talented and humble, with the pace, intelligence and eye for a goal to fit into Liverpool’s system and front line is something the manager would always be looking for. But why now, when they already have four world class forwards vying for three places?
The answer is two-fold. In four competitions still this season, Klopp knows he will have to rotate heavily for the remainder of the campaign, and needs more depth in an attacking unit that looked exposed in the absence of Mo Salah and Sadio Mane for the first leg of their Carabao Cup semi against Arsenal.
Yet it goes deeper than that. Liverpool do not spend £50m on back up players. That is the preserve of Manchester City, PSG and Chelsea. He has been bought to give the club continuity, as they evolve.
There is an analytics department at Anfield that is the match of any football club in the world. They already have modelling way beyond the usual metrics to measure a player's true worth, so he will has attributes to fit their system.
There is one other pertinent stat though, perhaps the most important one. Diaz is 25, and in the summer of 2023 he’ll be 26. By then, Sadio Mane, Roberto Firmino and Mo Salah will be 31.
There is no guarantee that all three of a famous front line will be offered new LONG TERM contracts, though all will surely be offered deals of some sort. Not all three may accept.
Diaz, in terms of style, numbers and position is most like Mane, but can also play on the right side. With his pace and wiry strength, he could quite possibly even play down the middle occasionally too.
So while he is the coming man of world football, he is also one for the future, as Liverpool look beyond their current success, to try to build an equally bright future. Depending on medical results of course.
