When Frank Lampard was questioned over Chelsea's poor defensive record in his tenure as manager, he suggested his goalkeepers were to blame.

Ahead of Tuesday's home game against Sevilla, which will kick off the Blues' Champions League campaign, it was put to Lampard that his side were conceding enough goals for him to rank him among the club's worst bosses ever in that category.

Indeed, Chelsea have conceded nine goals in their first five Premier League games this season – three coming in Saturday's 3-3 home draw with Southampton – and leaked 54 in the 2019-20 top flight, more than any other team to finish in the top 10.

"I'm aware of the stats and the other stat is we have conceded second least shots," said Lampard.

"That helps to narrow down the issue. It's something we are aware of with our recruitment and on the pitch with the players to make sure we set up well.

"We want to concede less, as do all teams at the moment."

As Lampard referenced with recruitment, Chelsea hope the signing of Edouard Mendy for around £22million from Rennes can solve their goalkeeping issues.

But is the statistic he cites correct and to what extent can the other keepers, Kepa Arrizabalaga and Willy Caballero, be blamed for the club's woeful defensive record? We have used Opta data to find out...

CHELSEA RANK HIGHLY IN PREVENTING SHOTS

Since Lampard took charge at the start of last season, Chelsea have conceded 89 goals in 62 games across all competitions, an average of 1.44 per game.

Of the 17 sides who played in the Premier League last year and this year, that puts Chelsea in the bottom half (11th of 17).

The best two records, by comparison, are held by the two Manchester clubs, with City (61 in 65) and United (63 in 67) both averaging 0.94 goals conceded per game. West Ham are the worst, with 1.58 (79 in 50 matches).

But, as Lampard suggests, there is a significant difference when it comes to shots faced.

Taking all competitions into account, the Blues have faced 590 shots across their 62 games, an average of 9.52 per game.

That ranks third of the 17 teams, only narrowly behind Manchester City (7.34 shots per game) and Liverpool (9.46), with Leicester City (9.76) the only other team facing less than 10.

Of the shots Chelsea have faced, 215 have been on target, an average of 3.47 per game which ranks fifth of 17. 

So, Chelsea have been reasonably effective in limiting the shots they face and the attempts their keepers have to save.

However, 15 per cent (89) of opposing teams' shots have resulted in a conceded goal and by that metric, Chelsea are worst of all 17 teams.

The best is Arsenal (eight per cent) and Manchester United also rank in single figures (nine per cent), so it seems Lampard has a point that his goalkeeping is the primary concern.

KEPA STATS MAKE ABYSMAL READING

Delving deeper into Opta's advanced goalkeeper metrics, we can look at expected goals and how their keepers rank in the goals prevented statistic.

Unfortunately, it makes abysmal reading for Kepa. 

There were 43 shot-stoppers who played a Premier League game since Lampard took charge of Chelsea and Kepa ranks last in goals prevented differential.

In his 36 league matches for Chelsea since Lampard took charge, Opta's expected goals system projects the Spaniard should have conceded 39.21 goals. The actual figure was 51, giving him a goals prevented ratio of minus 11.79.

For context, the next worst of those who played at least 25 matches in that time period, were England duo Nick Pope (minus 4.31) and Jordan Pickford (minus 4.17).

Caballero also has a negative differential (minus 3.73), conceding nine Premier League goals from his six matches when his expected figure was 5.27.

The best goalkeeping performance in that time has come from Tottenham captain Hugo Lloris (plus 9.87 goals prevented), closely followed by Martin Dubravka (plus 8.57), Dean Henderson (plus 8.35) and Vicente Guaita (plus 7.97) – with those four ranking well clear of the rest.

As a team, Chelsea have conceded 63 in the league since August 2019, while the expected figure is 44.74, their minus 18.26 differential being far and away the top-flight's worst.

Southampton are next worst at minus 9.91, while the best record is held by Sheffield United, who conceded 46 when they were expected to concede 56.59, giving them a plus 10.59 ratio.

The poor goalkeeping is highlighted further when looking at Chelsea and their big six rivals.

Chelsea (44.74), City (44.34), Liverpool (44.67) and United (46.61) all rank similarly for the Premier League goals they would have been expected to concede since the start of last season.

By contrast, Arsenal (62.73) and Tottenham (62.72) rank more poorly.

However, the actual figures show Chelsea (63) conceded the most of the big six, more than Arsenal (54) and Spurs (55), who were boosted by the positive differentials and fine performances of Bernd Leno, Emiliano Martinez and Lloris.

City (42) fared best, with Ederson (plus 4.47) ranking well, while Liverpool (46) United (48) finished up relatively close to their expected figures, all highlighting just how badly Chelsea have been let down between the sticks compared to their nearest competitors.

Chelsea will hope Mendy, once fully fit and settled, can resolve their goalkeeping woes, as it is clear the data backs up Lampard's statement.