N’Golo Kante has been as pivotal a figure as anyone in this modern era of Chelsea – an impact as great as that of Didier Drogba, Frank Lampard or John Terry.
That means replacing him when he picks up injuries is no easy task, with the France international again on the sidelines for a spell.
Thomas Tuchel’s dilemma was whether to risk going with a more attacking replacement against Leeds on Sunday, a relentless opponent who had started the season well under Jesse Marsch’s tutelage, or input another defensive-minded anchor alongside Jorginho. His choice ended up costing Chelsea the match.
There was a red-hot atmosphere in the Elland Road sunshine between two traditional fierce rivals – animosity that stretches back to when the pair were competing for the first division title in the 1970s.
A Raheem Sterling strike that flashed just wide with only 36 seconds on the clock almost silenced the home faithful, but they need not have worried, as the high-octane unit that Marsch has created soon had the measure of their opponents, and hit them where it hurt – right through the middle.
Connor Gallagher has more than earned his spot in the Chelsea side after his exploits at Crystal Palace last term, but his attacking instincts were of no use as Leeds simply pressed and pressed, not allowing the visitors out of their own half for long periods.
Without the Kante buffer, Chelsea were simply too brittle at their core. With the crowd cheering every flying challenge, Leeds won possession six times in the final third in the first half alone.
Gallagher did not play badly on his Chelsea Premier League bow, he was simply fulfilling a role his was not prepared for.
A better option would have been to go with Ruben Loftus-Cheek in the middle, with Cesar Azpilicueta filling the void at the back, but Tuchel’s gamble in the end proved costly.
The Chelsea boss realised the error of his ways at the interval, and switched to a back four, with Loftus-Cheek moved into a defensive midfield role alongside Jorginho, but by then it was too late.
The opening goal that set Leeds on their way to victory only came about thanks to a monumental error from Edouard Mendy, who not for the first time was guilty of trying too much on the ball, allowing Brenden Aaronson in to lift the roof off Elland Road.
It was no more than Aaronson especially deserved. The new signing covered almost six kilometres in the first half, nearly one kilometre more than anyone in blue.
Further pressure up the pitch forced Chelsea into conceding a free-kick less than five minutes after the opener, with Rodrigo heading home his fourth of the season to end the match as a contest from there on in.
Gallagher was moved further forward in the second half – where he can be more effective – but Leeds in this form and showing this desire were not going to let a two-goal lead slip for the second time in as many matches.
New Chelsea owner Todd Boehly has not been afraid to splash the cash in the transfer market, with Barcelona anchor Frenkie De Jong among the list of names the club are interested in.
After this display, where a talented Chelsea team were blown away by an intense, hard-working Leeds, Boehly’s priority may switch away from adding another centre-back to a renewed pursuit of the Netherlands international.
Jorginho is in there for his calming influence, but he needs a ball-winner alongside him, or another who can retain possession under pressure from teams like Leeds.
It was unfair to ask Gallagher of such at Elland Road. Now, with Kante set to be out for at least another month, Tuchel must learn his lessons, and resist going so gung-ho against certain opponents.
Otherwise, it could be quite clear where teams can do the most harm and get damaging results against a Chelsea team who need to start to justify such an extensive recent transfer outlay.
