Before Wednesday evening, the last time that Roman Abramovich attended a Chelsea game in the Champions League was when they were lifting the trophy in Porto on May 29.
The very next morning he shared breakfast with Thomas Tuchel, during which time he agreed to extend the German coach's contract at Stamford Bridge.
But this week, as he watched from his cushioned seat the Gazprom Arena, he saw the Blues produce a performance that could have a lasting effect on their bid to retain the European Cup in 2022.
Magomed Ozdoyev's stoppage-time equaliser for Zenit secured a 3-3 draw for the Russian outfit, and dropped Chelsea to second place in Group H, meaning the defending champions will be unseeded for Monday's last-16 draw.
A daunting tie against one of Bayern Munich, Real Madrid, Ajax or Lille now awaits them in late February, though Tuchel has far more immediate issues to address before he can even begin to think about the knockout stages.
Chelsea have conceded three goals in each of their last two games, while the only win they have recorded in their last four outings - a 2-1 victory over Watford - was described as being "lucky" by Tuchel himself.
Performance levels have clearly dropped, which is concerning the ex-Paris Saint-Germain boss more even than his side's points tally.
"It's absolutely not the moment to talk about individual performances, about whether we are happy or not happy," Tuchel began his press conference on Wednesday.
"Nobody can be happy."
With three Premier League games to come in the space of nine days against Leeds United, Everton and Wolves, the Blues must turn it around or history could very well repeat itself.
Around this time last year, Chelsea were top of the Premier League table and into the last 16 of the Champions League after cruising through their group.
Six weeks later, Frank Lampard was sacked, paving the way for Tuchel to take over and revolutionise the team's on-field displays.
Unlike in the final weeks of Lampard's tenure, Tuchel remains broadly popular across the Chelsea dressing room after leading them to European glory last season, but the bad habits that were evident during his predecessor's reign are threatening to return.
"It is true that at Chelsea, you don't need a big number of defeats in a row to call it a bad period or a crisis," club captain Cesar Azpilicueta told reporters on Wednesday.
"It is part of this club to go into every competition with the ambition to compete at the top. Last season, in December, we were top of the group and top of the Premier League, and we had a very bad run of results.
"Every year is different. We have different people, different players and it is just that we need everybody to get that extra percent as individuals, and as a team. At the moment we are making a lot of mistakes.
"We need to recover that high intensity, the solidity from the whole team to not concede chances."Getty/GOAL
If Chelsea do win their next three games and head into the festive fixtures on a positive note, then the past fortnight will soon be forgotten, and Tuchel's quality work behind-the-scenes will go back to being appreciated.
And yet he cannot control all the factors behind his side's poor run, particularly the number of injuries that have hit his squad, most notably in midfield where N'Golo Kante, Jorginho and Mateo Kovacic have all been struggling with their fitness in recent weeks.
Tuchel will not use that as an excuse, however, with the 48-year-old expecting the same standards from his fringe players as his star names; a policy that worked to perfection last season as he utilised the entirety of his squad during his first four months in charge.
Instead, Tuchel will be calling on his side to follow the mantra he instilled in them back when he arrived in January, that they be 'horrible to play against'.
His basic requirements of his team are non-negotiable, with his sides drilled to play high-intensity, 'gegenpressing' football which limits opportunities for opposition sides to counterattack.
In recent games, though, the soft underbelly that proved to be Lampard's downfall has made an unwanted reappearance.
"My analysis is very clear," Tuchel said. "Our behaviour changes when we have a lead, and this is something we never did and should never do. We do the things we want to do at the highest level and we push ourselves until it hurts - and it has to hurt.
"You have to be tired at half-time and fully tired [at the end]. You have to play through physical pain and raise your level of concentration and overcome adversity. Without all this, if you change your behaviour because of a result, you allow the possibility to be punished.Getty/GOAL
"If you are unlucky enough, like we are at the moment, then it can happen to you. The challenge is to close the door and minimise the possibility. It is very easy, we need a higher level of sprints, a higher level of running, intensity and concentration level.
"It is the basics, and the basics need to be pushed onto a higher level while we are in the lead. It cannot drop just because we are in the lead, and this is what is happening right now to us. It's not the big picture, but it is what it is."
If Chelsea are not able to produce those "basics" in the coming weeks, then their future opponents have been handed ideal blueprints by the likes of Watford, West Ham and Zenit as to how the Blues can be got at from an attacking point of view.
Their Champions League hopes have already been bruised, and they cannot allow the same thing to happen domestically, presuming Manchester City and Liverpool continue to be relentless in their own performances.
And so while Tuchel has already etched his name into the list of legendary Chelsea managers after his heroics in 2021, the sight of Abramovich staring down in Russia was a reminder of just how fickle life as the Blues boss can be.
He must overcome what is currently only a mini-crisis, otherwise he could be in for a rather more uncomfortable conversation with the owner than his Portuguese breakfast six months ago.