Cast your minds back to Autumn 2016. Liverpool were playing some of their best football under Jürgen Klopp and showing a ruthless streak against the lesser sides that many thought to be extinct. A title challenge appeared to be shaping up nicely.
The Reds took maximum points from games against Hull City, West Bromwich Albion and Swansea City but in each of the games a clean sheet eluded them.
All three sides scored what many would consider to be soft goals. Klopp's men failed to deal with a set piece and it resulted in a goal that more often than not they didn't deserve.
Many were prepared to overlook these problems because at the time Liverpool had the firepower to go toe-to-toe with most teams and win. After all, the one in a 6-1 scoreline isn't considered to be as important the six.
However, as the season has progressed the goals have dried up to an extent – dropping from 2.31 per game pre-2017 to 1.6 since the turn of the year . The attack is no longer able to mask the defensive problems and those in red are now suffering because of it.
On Sunday, Christian Benteke came back to haunt his former employers with two goals at Anfield to put a dent in Liverpool's Champions League push.
The Belgian nodded home the winner when he somehow managed to find himself free inside the six-yard box.
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It's not the first time it's happened and it certainly won't be the last time. The goal was the 22nd from a set piece Liverpool have conceded since the German took charge in October 2015.
This season alone the Merseyside club have conceded nine goals from set pieces. The list includes the likes of Calum Chambers, David Meyler, Leroy Fer, Gareth McAuley, Fernando Llorente, Richard Stearman, Alfred N'Diaye, Matthew Pennington and Benteke.
Klopp claimed back in October that his side don't have a problem defending after his side beat the Baggies 2-1 to go joint top of the Premier League.
“If people say we have some issues with set pieces, how can I say they are wrong? I think 70 to 80 per cent of the goals we have conceded are from set pieces. But they are all different and we are still working on it and we defended against Manchester United brilliantly. Against West Bromwich Albion it was so difficult but we have no defensive problem.”
The picture above is taken prior to McAuley lashing the ball home to halve the deficit. You can see three WBA players unmarked in or around the six-yard area.
It's not identical to the Benteke goal but there are some similarities, mainly how the opposition have time and space within the penalty area.
The former Borussia Dortmund manager tried, and failed, to downplay the fact his team have a set piece problem. He tried to sweep it under the carpet so not to attract unwanted attention to the team's Achilles heel.
Truth be told, it’s an epidemic and has been all season. These aren’t just isolated incidents either, it's happening almost every single match and opposition managers have taken note.
The worrying part from a Liverpool perspective must be knowing the German has known about it since October yet it's still happened in April and nothing was done in January to combat the clear problem.
Following on from the win at Anfield, Eagles boss Sam Allardyce made it clear in his post-match interview how he'd identified the Liverpool weakness and looked to expose it like all good managers would.
“I give the players a huge amount of credit for the way they defended and how they exposed the weaknesses of Liverpool defensively which, in the end, they couldn’t cope with,” he said.
“On the corners everyone knows Liverpool are pretty weak. They conceded six off corners which we told the lads about. It’s now seven off that corner that has got us the winner.”
Zonal Marking Problem?
The media will have you believe Liverpool's inability to defend set pieces is down to the system they use when marking the opposition. Klopp opts for a zonal system, as shown in the picture below, which tasks players with the responsibility of owning certain areas of the penalty area.
Certain players will look to block the opposition off so they don't get a free run at the stationary defenders but, for the most part, the players generally take care of their own set zone.
The system isn't the problem, the choice of personnel is. The opposition tend to create chances in the area for two reasons; players are ball watching coupled with individuals not knowing what they're supposed to be doing during the second phase of play.
In the picture above you see the Bournemouth player making a late run into the back post area before firing a shot just wide. Firstly, he's unmarked and his run isn't tracked. Nathaniel Clyne starts off in a deep area but comes centrally as the ball is played.
Secondly, look at the Steve Cook, circled in white, unmarked just outside the six-yard box. If the ball is a better one he's more than likely getting onto the end of that.
This time the pictures are from the build up to the Everton equaliser in the Merseyside derby. Initially Emre Can is keeping an eye on Phil Jagielka in a central area but the centre-back makes a dart to the near post and flicks the ball on.
The home side have men there but the Everton man has the run on them and manages to get a head on the ball. Three of his teammates anticipate this and make their move.
Dejan Lovren blocks the first attempt but Pennington is on hand to tap the ball home. He was the only blue shirt free in the six-yard box. Romelu Lukaku, the Premier League's top scorer, was also unmarked with the reds just switching off as soon as the first ball isn't won.
Similar scenario in the match against Swansea. The home side win the first ball, a header at the back post and this causes the Reds all kinds of trouble having already switched off. Three players in white are unmarked or goal side when the ball comes back across goal and Fer is able to poke the ball home.
It happened in the home match against Swansea too. The first ball was won in the air and knocked down, Wayne Routledge shielded the ball from Gini Wijnaldum before laying it off to an unmarked Llorente to fire home.
It's no easy fix. Liverpool transfer target Virgil Van Dijk won't arrive and solve these issues. It'll take the arrival of more intelligent players or a lot more time being spent on the training field with Klopp drilling home what he expects from each of his players in these situations.