CHELSEA fans would be wise to think about 96-97 ahead of the new season. I refer, of course, to 1196-97, when the legendarily imposing castle, Château Gaillard, was built by Richard I in Normandy.

Incredibly expensive, filled with the latest attacking technology and rumoured to be impregnable, Gaillard was set to dominate the European scene. Yet within a decade it had been besieged and captured, thanks mainly to some defensive flaws.

Chelsea begin 2020-21 with their own new set of attacking weaponry, in the form of Timo Werner, Kai Havertz and Hakim Ziyech, but if Frank Lampard can’t solve the issues at the back that plagued the club in 2019-20, the chances of a first Premier League title since 2017 will remain distant.

2004-05, Jose Mourinho’s first season in English football, remains arguably the greatest masterpiece of defending the nation has ever witnessed. In 38 games Chelsea let in only 15 goals, and two of those came after the title had been sealed. Goalkeeper Petr Cech had a formidable defence in front of him but still offered plenty himself on his way to an astonishing 24 clean sheets in 35 appearances.

Cech made 65 saves that season, which is 10 more than Kepa did in 2019-20 on his way to only eight clean sheets. Does that mean that the venerable Czech is three times the glovesman than Kepa? Not really, because that’s not how numbers work but if Cech’s 2004-05 is virtually unparalleled in purity, Kepa’s 2019-20 is now notorious.

Based on Expected Goals, Kepa let in around 11 more goals than the average goalkeeper would have done last season. As the shot map below shows, there’s the usual wide efforts that even a 15 foot Cech would struggle to reach, and there’s the tell-tale small yellow dots in the centre of the goal: easy, low quality chances that nearly everyone would stop, with or without a fresh pair of Sondicos on their hands.

The concerning ones are the relatively low quality shots that still slipped through. Take Wilfried Zaha’s thunderous goal for Palace against Chelsea in July. It had an xGOT of only 0.13, partly because it was from 30 yards but also because it really wasn’t anywhere near the top corner, instead it was virtually straight at Kepa.

It was hit hard, yes, but the ‘keeper had time to get his arms in the way, he just… didn’t. Kepa ended the season with a saves rate of 54%, the only first choice Premier League keeper under 60%. Put it this way, had Petr Cech had that ratio in 2004-05 he’d have let in around 42 goals. The Jose Mourinho era [UK Edition] would never have even got started.

But it would be as cruel as some of the tactics used at the siege of Château Gaillard to blame Kepa and Kepa alone. 54 goals conceded by Chelsea in 2019-20 was the most by the club in a league campaign since 96-97 (1996-97 in this instance) and you simply will not challenge for the league title if you let in that many goals.

In the Premier League era only Manchester United under Alex Ferguson (occasionally) managed to come top with a relatively leaky defence. United let in 44 goals in 1996-97, 45 in 1999-2000 and 43 in 2012-13 but each triumphant campaign was really the end of an era at Old Trafford (the Eric Cantona era, the dominant era of the treble winners and the entire Alex Ferguson era respectively).

Ipswich won the title in 1962 having let in 67, Sunderland in 1936 after conceding 74 but this offers no hope to modern teams. The starkest lesson is this: the last time Arsenal let in fewer than 30 goals in a season they won the league (2003-04). Defending is cool.

Chelsea’s defence has been bolstered by the arrival of Ben Chilwell and Thiago Silva but neither are expected to be fit to face Brighton this weekend. That means the boys of 2019-20 will have at least one more chance to show that they’ve spent the shortest of off seasons taking stock.

By the time Frank Lampard’s team play on the south coast they may well have confirmed the transfer of goalkeeper Edouard Mendy from Rennes for around £18m. Mendy had the third highest saves rate in Ligue 1 last season and would arrive from the same club Chelsea signed Petr Cech from back in 2004. Like with many medieval castles, sometimes the symbolism is more important than the fine details.