Jose Mourinho faces a decisive and defining moment as the beleaguered Chelsea manager bids to avoid a catastrophic exit from the Champions League against his old club FC Porto on Wednesday night.
The crisis-torn Premier League champions are languishing just two points above the drop zone having suffered a stunning 1-0 home defeat against lowly Bournemouth in the Saturday Night Football.
Chelsea need only a draw at Stamford Bridge in their final Group G fixture to be certain of a place in the knockout stages, but what in previous years would have been a forgone conclusion for a team managed by Mourinho now looks a decidedly more taxing task.
Once virtually unbeatable at the Bridge under the Portuguese, the west Londoners have lost four times on home turf and 11 matches in all competitions this season.
Porto, who need a win to be sure of progressing, are unlikely to prove a pushover after beating the Blues in Portugal earlier this season.
It would be the ultimate irony if Porto, where Mourinho made his name by winning the 2003 UEFA Cup and 2004 Champions League, deliver the final blow that ends his second spell with Chelsea.
And after so many unexpected setbacks this season, Mourinho admits he can take nothing for granted against his former employers, although they have been boosted by the news that captain John Terry and Ramires both trained on Tuesday and are available, but Radamel Falcao is still out despite taking a limited part in training.
"Falcao is not fit," Mourinho said during his pre-match news conference. "He just had a little period with us. It was the first time he'd trained with us. He's still a couple of weeks away from being in condition to play. John and Ramires look fine."
"It's a knockout game," Mourinho told Chelsea TV. "It's a group phase where normally you still play for points.
"But the reality is that it's a knockout. Chelsea or Porto, one will be out. For sure, a big game."
Dynamo Kiev are two points behind Chelsea and Porto and if the Ukrainian club fail to beat Maccabi Tel Aviv at home, Mourinho's men would qualify even if they lose to Porto.
"I'm actually less concerned about Porto this time," he said. "I have to focus 100 per cent on my squad, who will play, how we will play. Normally, I would be much more worried about a side like Porto, but at the moment I can only think about Chelsea."
Goalkeeper Thibaut Courtois, who returned to the line-up at the weekend after three months out, says Chelsea won't be playing for a draw: "If you play to draw, you never know what might happen in the last minute. We play to win, to give our fans a victory. We've lost a lot of games at home already this season, and it shouldn't be like that. We owe it to the fans to give them a win."
Porto's setback against Kiev on matchday five has left the Portuguese requiring a win to guarantee qualification. A draw could also be enough to go through, in first as well, but only if Kiev don't win.
Julen Lopetegui's side warmed up for their trip with a 2-1 win over Pacos Ferreira on Saturday with goals by Jesus Corona and Miguel Layun, who is on loan from Premier League Watford. The win extended their unbeaten run in the Portuguese league to 12 matches.
Opta Stats
Chelsea have won all three home Champions League games played versus Porto; the London side have scored exactly one less goal from the meeting before however, they scored once last time.
They have never kept a clean sheet against the Blues (seven previous meetings).
Porto have travelled to England 16 times previously in European competitions but have never won there (D2, L14); failing to score a single goal in four of their last five visits.
Chelsea have only lost once in their last 37 home Champions League matches in the group stage (W28 D8), that was against Basel in September 2013.
Charlie Nicholas' predictions
Well this is the most confusing thing I've witnessed with a club of this stature. We're playing a guessing game week by week trying to work out what we're going to get from Chelsea.
I said last week, I don't know why Jose Mourinho wants to keep playing Cesc Fabregas in a deeper role. His influence has to be creative, not work ethic. He's not got the pace about him but he has speed of mind to open things up, just as he did last season with his assists for Diego Costa and Eden Hazard. Willian seems the only man to keep them going.
I think Mourinho had to leave Costa out after the incident last week but I think he'll bring him back on Wednesday night as his job is genuinely on the line. I never thought I'd say that about Mourinho. I don't think they'll make the top four now so what have they got to play for if they go out?
They still need to draw and I think they'll fall over the line with a potentially uncomfortable but ultimately successful night.
Charlie predicts: 1-0 with Costa to score first (18/1 with Sky Bet)