Real Madrid have long been in need of defensive reinforcement and Porto's Eder Militao has been singled out for long-term success at the Santiago Bernabeu.

Madrid made the announcement on Thursday that Militao, 21, will join the club at the end of the season, signing a six-year contract.

When Porto brought him in from Sao Paulo in August last year, they managed to insert a €50million release clause, which was then due to increase by 50 per cent to €75m in July.

While that figure may seem significant for a player many might consider to be a relatively unproven talent, the apparent release clause increase suggests why Madrid moved to get the deal done early.

And, although Militao may be somewhat unfamiliar to wider audiences, experts have been hugely impressed by his brief time in Portugal.

"The complete package"

Despite his relatively tender age, Militao's game is already well-rounded, combining physicality, athleticism and technical ability.

He earned his first Brazil cap last year and appears destined for many more, particularly having really found his place in the centre at Porto after initially emerging as a right-back with Sao Paulo.

There are few areas in which Militao is weak, and Madrid fans can certainly expect to see a wide range of skills on display from next season.

"Militao is very complete," Portuguese football analyst Tiago Estevao told Omnisport. "That distinguishes him from most other young centre-backs and generally from most other centre-backs who have left Portugal on big-money moves over the last few years.

"He's highly successful in physical and aerial duels in either box, he's quick, good defensively and smart positionally off the ball.

"On top of that, he offers a lot with the ball at his feet both in terms of passing and progressing. He's the complete package for a modern, ball-playing centre-back."

Another of the Primeira Liga production line

It is fair to say Portugal's top flight has a superb record for discovering, developing and churning out serious talent.

Most might immediately think of Cristiano Ronaldo, Luis Figo, Rui Costa and other attackers, but plenty of defenders have gone on to impress around Europe after leaving the Primeira Liga.

While most of them have perhaps been missing one particular attribute or trait, Militao might just be the pick of the bunch, or so Estevao believes.

"They [previous big-money centre-backs] have done well, for the most part [when leaving Portugal]," he added. "But there was always something [lacking].

"Victor Lindelof perhaps missed the physicality, Nicolas Otamendi was mistake-prone, Ezequiel Garay was questioned for his pace and Willy Boly seemed to have the skill, but he wasn't a starter here. Militao is complete."

A shrewd investment

Even in this age when transfer fees seem to be getting more outrageous by the week, €50m looks a lot for a 21-year-old who has less than a full season's experience in European football and just one international cap.

It is also worth remembering that he has not spent all of his young career at centre-back. However, such is his ability and the way he swiftly adapted after moving from Brazil, Militao looks destined for the top.

"I do think his versatility is somewhat overstated. He is a competent right-back, but he offers nowhere near as much going forward from a wing-back role as what is expected from a Real Madrid – or even Porto – full-back, but even that's not a flaw, versatility is always a bonus," Estevao said.

"As soon as he arrived [in Portugal], pretty much everyone realised how good he was, which made sense. His stats in Brazil were impressive already.

"He's up there with the best young centre-backs [in the world] in my eyes. I definitely see this price tag as worth it."