Had Paul Garita been taken into a side room at half time ahead of a psychological assessment, it is possible the hulking Cameroonian forward on loan at Plymouth Argyle from Bristol City would have been diagnosed with some form of acute sorrow due to his lack of interaction with other human beings.

Liverpool were not spectacularly bad here. Their domination of Plymouth was almost absolute and the only shock that ever seemed likely to happen was the possibility of a draw and therefore a replay at Home Park the week after next.

And yet, Liverpool did not do enough to win; failing to perform with the level of speed necessary to out-think and break down an opponent, which quite understandably had only one target in mind: the result that transpired.

When you see squad numbers like 53, 54, 58 and 66 on the teamsheet you know straight away that a side is weakened. It was, in fact, the youngest Liverpool XI in history, with an average age of 21 years and 296 days. Never before had it been below 22, with the previous record being set against Wolverhampton Wanderers ahead of the club’s first FA Cup final in 1965. Had Lucas Leiva not been selected as captain on the eve of his 30th birthday, it is possible the mean would have been even lower than it was.

Emre Can grabs hold of possession for Liverpool (Getty)

Plymouth deserve credit for their perseverance and organisation. Their supporters had queued from 3am in the cold of late December to purchase tickets for this match. They had risen early again on Sunday – at 5am - to begin the seven-and-a-half-hour journey to Merseyside and eight thousand and six hundred of them took up the entire Anfield Road stand.

Liverpool probably needed to score early in order to intercept rising confidence in the away end. Despite losing at Barnet in their last game, Plymouth – like Liverpool – are second in their division, though that division is League Two.

The danger for Liverpool - especially with so many young players involved against an opponent happy to let them have the ball - was blatantly obvious. This could become the type of tippy-tappy game you see at many academies or sometimes don’t see when one of those behind closed door friendly matches are held at training grounds.

Joe Gomez tussles for the ball with Jordan Slew (Getty)

For the majority, indeed, the pattern was consistent: 21 players being camped in the Plymouth half of the field; Liverpool passing it this way and that way, making Plymouth chase and chase before regrouping – which they did superbly.

In the first half, Sheyi Ojo and Ben Woodburn did not convert Liverpool’s best opportunities and when Divock Origi did find a way past Luke McCormick, the Plymouth goalkeeper, he was penalised for having his arm placed around the neck of Gary Miller, the Glaswegian right back.

It seemed to be a matter of whether Liverpool could increase the pace at which they were operating and whether Plymouth’s attention levels could continue – whether, perhaps, the scoreline would encourage them to the point where they decided to attack and leave Liverpool with enough space to punish them.

Ben Woodburn attempts to get a shot off on goal from a tight angle (Getty)

Liverpool players, though, were still taking too many touches. Plymouth’s first shot on target came in the 55th minute: a left-foot free-kick from midfielder Graham Carey, who was raised in a Liverpool supporting family from Blanchardstown in Ireland before being picked up by Celtic.

At that point, Liverpool had registered 13 shots of their own, although it was reflective of the proceedings that only two of them had forced McCormick into action.

Daniel Sturridge was sent on for Emre Can and this increased Liverpool’s options in attack. Then came Adam Lallana for Ovie Ejaria and Roberto Firmino for Woodburn, whose full-Liverpool debut was not quite as magical as his first substitute appearance where he became the club’s youngest scorer.