Frank Lampard's Chelsea may be one of the best at restricting opposition shots, but they are the worst in the Premier League when it comes to making glaring errors that lead to goals.
Under-fire keeper, Kepa Arrizabalaga, is the principal offender, but he is not the only one to blame in the Blues line-up.
Since the beginning of last season, players from all departments in the team have chipped in with mistakes that ultimately gifted their opponents a goal.
Lampard has come in for criticism over his side's defensive record after shipping nine goals in the Premier League this season and 63 in 43 games since he took over at Stamford Bridge. And during that period Opta analysts estimate that, based on the number and quality of shots, the Blues should have expect to let in just 45.
Lampard pointed out ahead of tonight's crucial Champions League tie against Sevilla, that he, the staff and players are working hard defensively and, in fact, only Manchester City have conceded fewer shots since the beginning of last season - facing a total of 320, compared with Chelsea who have faced 379.
It is a useful observation and an impressive performance, but the truth is that for all Chelsea's good work it is being undone by moments of madness.
It must be incredibly frustrating for Lampard, who spoke about the issue in a press conference yesterday.
'The issues are that we don't concede too many shots on goal, but when we do, we concede goals,' Lampard lamented. 'It’s something we are aware of; we were aware when you look at our recruitment. '
That recruitment includes £22m for goalkeeper Edouard Mendy from Rennes as a replacement for the £72m Kepa, who came from Atletico Bilbao at the beginning of last season.
It also includes the acquisition of the experienced Brazilian defender Thiago Silva on a free transfer from Paris Saint-Germain.
And crucially the recruitment of a respected defensive coach, Anthony Barry, from Wigan this summer, who reportedly was on the same coaching courses as Lampard.
However, this season, Chelsea top the league for errors leading to goals with five, second are Liverpool with three.
From the 57 shots they have faced this term, Opta's analysts estimate less than six should have hit the back of the net, when the actual figure is nine.
It's grim reading for Kepa, of course, who has been blamed for three of the gaffes, partly because it only measures the final mistake before the ball goes in.
One of those errors was Kepa's stuttering defence again Southampton's Che Adams at the weekend. But surely defender Kurt Zouma has a big share of responsibility for the appalling back pass that put his goalkeeper in trouble and allowed Adams through on goal?
Other culprits this season include Thiago Silva, whose uncharacteristic mistake allowed Callum Robinson to race through and make it 2-0 to West Brom, and Kai Havertz, who acknowledged his error when he let the Saints in for a game-changing goal while Chelsea led 2-0 on Saturday.
Looking all the way back to the beginning of last season, the period Lampard is highlighting in establishing his defensive credentials, the list of unfortunate moments extends to include N'Golo Kante who has copped for two errors leading to goals and Antonio Rudiger, who is responsible for one.
Unless Lampard can find a way to eradicate these regular occurrences, they will simply nullify his team's assault on the Premier League title and progress in the Champions League, despite over £250m of investment.
'Chelsea are not contenders [for the title],' Jimmy Floyd Hasselbaink definitively declared on Sky Sports after Southampton pegged them back to 3-3 after they led 3-0. 'They are leaking too many goals.
'The defence is a worry, if they cannot improve the centre backs and goalkeeper it is a concern. Alisson wins Liverpool points, but that doesn't happen with Kepa. Chelsea need to improve in that area.'
Indeed, while many members of Chelsea's team should put their hand up in the blame game over goals conceded, it is the keeper, Kepa, who carries the greatest responsibility.
Looking at the shots faced on target by Chelsea in the last 14 months, Opta calculates a figure for the number of goals an average goalkeeper would be expected to concede based on the quality of shots faced.
In Chelsea's case, almost 16 goals have rattled the net since the beginning of last season, which could quite clearly have been prevented.
Lampard, who has spoken of the need to give his embattled keeper confidence, will be desperate for his new recruit Mendy to regain his fitness and take his place between the sticks before this season's targets in both the Premier and the Champions League slide out of view.
Source: m.allfootballapp.com