For most of the Premier League era, full-back has been a problem position for Liverpool.

Sure, there were successes from Rob Jones and Stig Inge Bjornebye to Steve Finnan and John Arne Riise, but the majority were either overpriced, inconsistent, injury-prone or just not very good.

Until Trent Alexander-Arnold and Andy Robertson came along.

The duo have established themselves as the very best in their respective positions at right and left back in world football, having shone during the Reds’ rise to domestic and European glory under Jurgen Klopp in recent years.

Such is their importance under the German, Saturday’s victory over Crystal Palace was Liverpool’s first Premier League match without either in the starting XI since December 2018, when winning 3-1 away at Burnley, and the first at Anfield since drawing with Chelsea 1-1 in November 2017.

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Crucial to how the Reds play, bombing forward and registering assists galore without such a style coming at the expense of their defensive duties, such is their consistency, fans will have virtually forgotten the anxiety that used to greet them when seeing wingers attack their full-backs of yesteryear.

While such a set-up has proven revolutionary at Anfield in recent years, that perhaps wouldn’t have been the case had Rafa Benitez successfully landed one of his most-desired targets in the summer of 2006.

Liverpool were famously close to signing Brazil legend Dani Alves from Sevilla, with the now 38-year-old going to establish himself as one of football’s deadliest attacking full-backs.

Just not at Anfield.

“I pretty much had an agreement with Liverpool,” the Brazilian told FourFourTwo in 2017. “But for whatever reason it didn’t happen at the last moment and I really don’t know why, as I wasn’t the one conducting the negotiations. I had other people representing me back then.”

Alves would go on to join Barcelona two years later, and would end up winning six La Liga titles and three European Cups during a trophy-laden eight-year stint at Camp Nou which set him on his way to becoming football's most decorated player, with his Olympic Gold medal with Brazil this summer the 43rd major honour of his career.

It’s easy to say in hindsight but former Liverpool CEO Rick Parry admits the Reds made the wrong decision pulling the plug on the deal.

“We had the deal - finally, after enormous complications - tied up for Dani Alves and then the decision was should we buy two players or should we spend all of that on a full-back?” he told BBC Radio Merseyside in 2017.

“Alves was not the player then that he is now, but he always looked like he would be a great player.

“Would he have been a better signing than [Jermaine] Pennant and [Peter] Crouch, for example? Probably yes, but it's easy with hindsight.

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“Looking back, if I could do anything different, it would be to focus on buying one [player] at a time rather than having to buy five or six every season.”

Benitez remembers things slightly differently, as demonstrated by the fact that Crouch actually joined Liverpool a year before they made their move for Alves, revealing he was left with a difficult choice between signing the Brazilian or bringing in Dirk Kuyt - who coincidentally joined the Reds on this day yesterday back in 2006.

“One option whom I had been alerted to was Daniel Alves, the Brazilian right-back, who was available from Sevilla. We had been tracking him since his early days in South America and we knew he was a very good player.

“We only had funds though, for one purchase. We needed a striker and, with money limited, it was better to fill that slot than sign a full-back to play as a winger. We signed Kuyt.”

Such a decision is easy to curse looking back, especially when it is reported Liverpool had agreed a deal to sign Alves for just £8m.

Kuyt signed for £10m, after the Reds had already brought in Jermaine Pennant and Craig Bellamy for a combined £12.7m, with Alvaro Arbeloa following in a £2.5m deal the following January.

Afterall, had the Reds landed the Brazilian then perhaps a long-held problem position would have been solved much earlier.

But now, 15 years on from Liverpool’s initial failure to land Alves, could they revisit their long-extinguished interest?

With Alexander-Arnold and Robertson ensuring Klopp’s starting slots are secure, supporters’ attentions turn to the reserve ranks instead as they analyse whether the German boasts suitable depth in every position.

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Any doubts at left back will have been eradicated by Kostas Tsimikas’ start to the season, with the Greece international quietly emerging as a cult hero having already been afforded more Premier League action than he managed in the entirety of last year.

In the past, the absence of Robertson from a starting XI would have been greeted by anxious murmurs, but the 25-year-old's showings a year on from his move from Olympiacos, show that Klopp’s faith in his talents was well-placed.

But it’s a slightly different story at right-back, with James Milner filling in for Alexander-Arnold against Palace in the absence of Neco Williams, who missed out through illness and injury respectively.

The Wales international had been expected to leave Anfield in the summer only for a move to fail to materialise, and does have his critics among certain sections of the Reds’ fan-base.

But so too does vice-captain Milner, who is out of contract next summer, with the 35-year-old’s inclusion up against Wilfried Zaha causing fresh to supporters against the Eagles on Saturday.

Despite suffering two red cards at the expense of the Ivory Coast international in the past, fans needn’t have worried about the veteran.

Yet there will be some that are still keen to see Klopp add a new right-back to his squad to make a similar reserve impression as Tsimikas where such a change is more like-for-like than potential weakness.

And this is where Alves comes in.

The Brazilian is now a free agent after his contract with Sao Paulo was torn up earlier this month, despite helping them win the Campeonato Paulista league last season, following a dispute over unpaid image rights which resulted in him refusing to report for training after international duty.

"Daniel Alves and Miranda were serving the Brazilian team and should have returned to start regular training for out next games [on Friday]," Sao Paulo's footballing director Carlos Belmonte confirmed when explaining the situation.

"Miranda attended and trained normally, but Daniel Alves did not attend. We were then informed by his representatives that Daniel Alves will not return to Sao Paulo until the settlement of the debt that Sao Paulo has with the athlete.

“A debt that Sao Paulo recognises and last week made a proposal seeking the right outcome, which was not accepted by the representatives.

“From our point of view, we have taken the decision that Daniel Alves will no longer be available to play for Sao Paulo. Sao Paulo is more important than all of us."

Despite his age, Alves has no desire to hang up his boots just yet with the right-back still keen to represent Brazil in next year’s World Cup.

As such, could he continue his career in the Premier League and follow in the likes of former Juventus team-mate Cristiano Ronaldo’s footsteps?

He might be 38 but, as Thiago Silva proved once again for Chelsea on Sunday against Tottenham Hotspur, write off world class Brazilian veterans at your peril.

Admittedly, the thought of Liverpool signing Dani Alves on a free to serve as an alternative to Trent Alexander-Arnold doesn’t seem a particularly realistic one.

Besides, despite his free agent status he would not be free to join an English club until January having seen his contract terminated following the close of the Premier League transfer window.

But there can be no doubt about his quality and there would be some supporters who would be tempted by the possibility of the veteran sharing his experience at Anfield and potentially adding to his haul of 43 trophies.

Yet don’t Klopp to be one of them.

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There would have been a time in the not-too-distant past when supporters would have urged the club to make such a signing to bolster their ranks, but perhaps, if Saturday’s victory over Palace is anything to go by, the Reds’ reserves are good enough after all.

Even if Milner departs Liverpool at the end of his contract next summer, he continues to serve the Reds well regardless of the position he is asked to fill.

Meanwhile, even when Williams was being tipped to depart Anfield, club insiders insisted the German was happy with the options at his disposal with high hopes held for Northern Ireland international Conor Bradley, who could make his debut against Norwich City on Tuesday.

Their names might not be as glamorous as a new signing or the lure of Alves, and there will be some that continue to question Liverpool’s depth and the quality of the players they have in reserve.

But Tsimikas is the perfect example of Klopp knowing the strengths of his squad and knowing exactly what he is doing.