STAMFORD BRIDGE, London — Chelsea's Champions League dream wasn't ended by Paris Saint-Germain on Wednesday—the real damage was done a year ago.
It was at the same stage last season that the Ligue 1 champions dumped the Blues out of the competition. Rather than learn their lesson from that sobering night in west London, Chelsea have failed to evolve and adapt, so now they're paying the ultimate price.
There's no more Champions League for them this season and with a place in the Premier League's top four long since gone, there won't be next year either. And they only have themselves to blame.
The frailties that got Chelsea eliminated from the Champions League 12 months ago still remain. This squad lacks real depth and that results in them struggling to react to what happens around them. Just a couple of injuries can completely change the complexion of the side, as we've seen now; the Blues have also been found out for their reliance on a few key players to win them matches.
There's a saying about how history repeats itself first as tragedy, second as farce. Chelsea embodied that sentiment at Stamford Bridge on Wednesday.
Until Diego Costa's injury forced him off, Chelsea were well in this tie. They were more than matching PSG and with a boisterous home crowd behind them, they seemed to be summoning up the spirit from seasons past when they clawed their way through difficult moments.
Then the Spain international limped off and Chelsea's hopes of overcoming PSG drifted off into the ether. With no Costa to consume them at the back, Laurent Blanc's side weren't looking over their shoulder anymore; the defence visibly stepped 10 yards further forward to congest midfield and dominate.
Within seven minutes of Costa's exit, Zlatan Ibrahimovic was scoring the winner—his second goal in the tie.
Last year Chelsea failed against PSG because Cesc Fabregas and Eden Hazard didn't turn up. They weren't dynamic enough and eventually it allowed the French team to completely dominate. This year everything depended on Costa, so when he could no longer carry this team in attack, it was left to 20-year-old Bertrand Traore to pick up the reins. Looking at their bench, Chelsea had no other proven candidates.
The young striker's time will come, but Wednesday belonged to Thiago Silva and David Luiz where Traore was concerned. He was toast against two experienced centre-backs, who chewed him up and spat him back out. It left Chelsea doomed, resigned to a fate they had long since sealed themselves.
That's where the depth of this Chelsea side becomes an issue. Why, for all their investment, are the Blues relying on a select few to deliver consistently? Why can't they rotate sufficiently to deal with the demands of modern football? Why can't they adapt their tactics to meet the different challenges across a season?
The problems were clear 12 months ago, yet for whatever reason, Chelsea didn't react. The squad needed more depth in midfield to add bite and authority; in attack they needed an extra spark to complement what they already have.
Outside of Pedro, no other players arrived in those key areas. Maybe if they had, Hazard's disappearing act wouldn't have been so keenly felt. Even defensively Chelsea have left themselves depleted, selling Filipe Luis without a replacement in place to start the campaign with just five first-team defenders.
It's decisions such as that which have resulted in Chelsea starting a last-16 match in the UEFA Champions League with an attacking midfielder at left-back. For all his efforts, Kenedy was always going to be suspect against world-class opponents on Wednesday, as he proved.
PSG learned their lesson from two years ago when they were on the receiving end of a Chelsea victory in Europe. Rather than fooling themselves that things didn't need to change, they have addressed their shortcomings and are stronger for it. Now they've got Chelsea's number.
Indeed, while Chelsea were toiling over their transfers last summer, PSG were busy strengthening the side that had toppled them, signing Angel Di Maria from Manchester United. And yes, you've guessed it, it was the Argentinian who executed the decisive cross to assist Ibrahimovic with Wednesday's winning goal.
Now Chelsea must listen to Guus Hiddink to avoid this happening again.
"Chelsea are now in a transitional period and they now have to see how to go on to try to regain the lost terrain where they used to be," said the Blues' interim boss at the final whistle.
That means dissecting this season with an element of urgency. Chelsea must act ruthlessly by addressing the problems that have got them to where they are.
Chelsea are barely a top-10 side right now and with their Champions League hopes dashed, the earliest we will see them back on Europe's biggest stage is in 2017/18—if they can qualify.
When they were running away with the Premier League title last year, it would have been madness to predict this spectacular fall from the grace. But the writing was on the wall when 10-man PSG got one over on them and nobody was listening.
Chelsea have to now. There's too much riding on it for them not to.