It was the last thing Antonio Conte or any Chelsea fan would've wanted to see; N'Golo Kanté limping off with an apparent thigh injury while on international duty with France.
You see, Kanté doesn't do injuries. Since he arrived in the Premier League in the summer of 2015 he has only missed one match because of a problem with his body – and that was while he was at Leicester City.
So if he is unable to play against Crystal Palace at the weekend, and the early suggestion is he will, then Conte will be forced into shuffling his already depleted midfield pack.
With Kanté ruled out and Danny Drinkwater still recovering from a calf injury, Conte has only two match-fit central midfielders at his disposal; Tiémoué Bakayoko and Cesc Fàbregas.
It is a far from ideal situation for Conte but given the Blues' opponents this weekend are Palace, who are bottom of the table and are yet to score, it's one he can probably live with.
However, if Kanté , who has been nominated for this year's Ballon d'Or, is ruled out for a prolonged period and misses further Premier League games and the Champions League fixtures against Roma, then Conte may have to improvise.
And that may mean once again turning to David Luiz to solve a midfield problem.
The Brazilian has played almost exclusively as a centre-back since he returned to the club from PSG in the summer of 2016 and has changed the opinion of many who doubted his defensive ability.
In the heart of Conte's back three, Luiz was the figure of consistency during the 2016/17 campaign and was a big reason why the Blues clinched the Premier League title.
He rewarded Chelsea and Conte's faith. The Italian had made it clear when Luiz returned to Stamford Bridge that he considered the 30-year-old – who often was used in midfield during his first spell with the club – a defender and nothing more.
“I think David Luiz is a centre-back, he's played a lot of games in that position,” the Italian told Chelsea TV.
“I know sometimes he's played as a central midfielder but in my mind the idea is to utilise him in the right position which, for me, is centre-back.”
However, less than two weeks into the 2017/18 campaign Conte deployed Luiz in the Chelsea midfield. It was against Tottenham at Wembley that the Brazil international was stationed as the holding midfielder in front of the Blues' back three.
The role was not an unfamiliar one for Luiz. During his first spell at Stamford Bridge, he played 30 times as a defensive midfielder, including in a Europa League final win over former club Benfica in 2013. So while he may have been rusty in the position, he wasn't a novice.
Chelsea clinched an important 2-1 win over one of their title rivals with Luiz making a crucial tackle in the build-up to Marcos Alonso's late winning goal.
But was Luiz's overall performance that day good enough to suggest he can once again be used in midfield in Kanté's absence?
Conte, for one, was impressed. He said: “David played very well. It was an amazing performance from him. He played with great experience and personality. He was a really important reference for the other players.”
They are kind comments but that is the sort of praise you would expect from a manager when speaking to the press. In truth Luiz was a little rough around the edges against Tottenham and to the untrained eye looked slightly lost.
He conceded fouls in dangerous positions and his passing wasn't on point, but that wasn't what he was in the team to do.
“My job was to run,” Luiz admitted afterwards. “I was running a lot. I had to cover the space of fantastic players like Eriksen and Dele Alli. They always play very well between the lines so I was trying to close this gap and not leave space for them to create.”
Luiz made five tackles, one of which led to the winning goal, one interception and four clearances against Tottenham. His overall defensive actions (10) in that game were more than Kanté (9), who admittedly was playing further forward, and Bakayoko (7).
And intriguingly, neither Kanté or Bakayoko have managed ten defensive actions in a game this season. So, while he may have been a little ragged at Wembley, Luiz was effective.
The is a school of thought that Luiz is at his best when he isn't given too much tactical responsibility but, since he has returned to Chelsea, that has been proven wrong.
Give him clear and direct instructions, as Conte has done when using Luiz in defence, and he can thrive. There is nothing to suggest the Blues boss couldn't do the same with Luiz in midfield.
Conte was a fine defensive midfielder in his playing days, he is a man who knows the role inside out.
With him improving Luiz in training and guiding him through games, there is no reason to suggest the floppy-haired Brazilian couldn't become an effective holding midfielder for Chelsea when required.