It was the 10 days last summer during which Chelsea could not get in touch with their head coach that the relationship between the club and Antonio Conte became impossible.
And there has been some sense of revenge about the way in which the Blues left Conte in the dark over his future after May's FA Cup final success, even allowing him to return for the start of pre-season training on Monday.
There were few congratulations from on high after Conte's team beat Jose Mourinho's Manchester United. Instead, there was largely silence that lasted until the inevitable was finally conveyed after he took training yesterday.
Whatever the reasons behind it, Conte's disappearing act sent Chelsea into a state of panic and convinced them he wanted out. Peace talks were hastily arranged and a new contract was eventually signed as a reward for winning the Premier League title. But, tellingly, there was no extension.
Nobody could be sure Conte would not pull a similar trick again and Chelsea did not want to be liable for more than one year's money if, as has transpired, they decided to sack the Italian.
It was not just Chelsea who had become suspicious, however, as Conte also lost faith in his employers during a summer in which he felt none of his main targets were signed.
Conte wanted Romelu Lukaku, Alexis Sanchez, Alex Sandro and Virgil van Dijk, but by the time Chelsea returned for pre-season on July 10 last year Lukaku had joined Manchester United instead and the Blues' only outfield signing, Antonio Rudiger, was not ready to start training after playing in the Confederations Cup for Germany.
With a Premier League trophy to use as a bargaining chip against club policy, Conte felt empowered to take on his employers. He warned people their jobs were on the line and that they would see 'the real Antonio Conte' if he did not get what he wanted.
He is still rated as one of the best coaches the club has ever employed, but there is a feeling that Conte's judgement became clouded at key points by an obsession to prove he was right.
There was bemusement from within the squad when he called a pre-season meeting to supposedly welcome Chelsea's new signings and introduced Paolo Vanoli and Davide Mazzotta, who had joined his backroom staff.
For a short while nobody knew whether or not Conte was being serious, but it quickly became clear that he was underlining the fact there were no new players to show off.
Of course, one player who had not been part of the pre-season meeting was Diego Costa, who effectively went on strike in Brazil after being informed he was no longer part of Conte's plans over text message.
That move went down spectacularly badly inside the Chelsea boardroom, as Conte had acted without their approval and had risked damaging Costa's value.
The message was also forwarded throughout the Chelsea squad, who were astonished that the club's top scorer in their title-winning campaign could be treated in such a way - even though he had been causing problems since rowing with Conte last January.
More difficulties with members of his squad surfaced during the season, as Conte dropped David Luiz after the Brazilian was perceived to have questioned his tactics during a stormy inquest in which Kenedy was given a dressing down for yawning. Injuries contributed to his absence, but Luiz only played five times after October's thrashing in Rome and Kenedy was loaned out to Newcastle United in January.
The 5-0 victory over Stoke on New Year's Eve meant that, despite all the angst, Chelsea finished 2017 still second in the Premier League and in all of the cup competitions.
But tensions boiled up again during a January transfer window in which Conte wanted backing with bids for Sanchez and Sandro, whom he believed were available. In the end, he had to be content with Olivier Giroud, Emerson Palmieri and Ross Barkley.
Conte had nothing against Giroud, who proved to be a shrewd addition, or Emerson, but felt that, while United were pushing the boat out for Sanchez, Chelsea were trying to strengthen from the substitutes' benches of Arsenal and Roma.
Any hope of Champions League qualification was effectively eradicated by the successive defeats to Manchester United and City, when Conte's tactics were widely condemned, along with his use of Eden Hazard as a false nine.
Hazard had been prepared to sacrifice himself for the supposed greater good up to that point, but sometime after the City loss the Belgian was pulled aside by Conte and had his commitment questioned.
Chelsea have desperately been trying to convince Hazard to sign a new £300,000-a-week contract, but word quickly got round that he was becoming annoyed by his head coach and it showed on the pitch.
The FA Cup final success provided some consolation, but not even that could mask the disharmony in the background as Willian posted a picture on social media of the squad celebrating with carefully placed trophy emojis to hide Conte.
Luiz and Willian would have never played for Chelsea again while Conte was in charge and there is every likelihood others would have been frozen out as well.
In his post-match press conference at Wembley, Conte repeated seven times 'I can't change' which pretty much told Chelsea everything they needed to know and had Roman Abramovich reaching for the reset button once again - even if it took some time for him to press it. (© Daily Telegraph, London)