Jose Mourinho's future as Chelsea manager could be on the line when his former club Porto arrive at Stamford Bridge on Champions League matchday six.
Group G is poised for a dramatic finale on Wednesday, with Porto and Chelsea tied on 10 points at the top - the Portuguese side edging their English rivals thanks to a 2-1 win in the reverse fixture.
Dynamo Kiev are third on eight points and all three teams are still able to progress to the round of 16.
The Premier League title-holders will secure top spot in the group and a potentially favourable opponent in the first knockout stage with victory in West London.
If Porto and Chelsea draw and Dynamo win at home to eliminated Maccabi Tel Aviv, the Ukrainian side will claim first place on goal difference as part of a tie-breaking mini-league between the three teams that are still in contention. That scenario would result in the Blues finishing second and Porto dropping into the Europa League.
Should the Primeira Liga powerhouse earn all three points and Dynamo also triumph, Chelsea must make do with UEFA's second-tier club competition.
The same fate befell them in 2012-13, when the team went on to win the Europa League under interim manager Rafael Benitez.
Roberto Di Matteo, having orchestrated an unlikely Champions League triumph in 2011-12, paid the ultimate price for his failure to prolong Chelsea's defence of the trophy a season later, receiving the sack in November 2012.
Mourinho himself is well acquainted with the potential cost of failure in Europe. The Portuguese manager's first spell in charge came to an end when the team opened their 2007-08 Champions League group stage campaign with a 1-1 draw at home to Rosenborg.
That parting of the ways may well have had more to do with a breakdown in Mourinho's relationship with owner Roman Abramovich than on-field performance.
Indeed, all was not lost in continental competition, as Mourinho's replacement Avram Grant then guided Chelsea agonisingly close to Champions League glory, losing the final on penalties to Manchester United.
Chelsea's results this season have been significantly worse than the run which prompted Mourinho's departure eight years ago.
In one of the worst starts to a defence of the Premier League, the Blues have managed to claim just 15 points from 15 matches played to sit 14th, 17 points behind leaders Leicester City and 14 points outside the Champions League qualification places.
The likelihood that Chelsea will fail to qualify for next season's competition through the Premier League makes it particularly important for Mourinho's men to stay alive as long as possible this term.
The hosts will be without midfielder Ramires and on-loan striker Radamel Falcao through injury, while John Terry is pushing to return from an ankle problem suffered against Maccabi Tel Aviv last month.
Porto, meanwhile, could start with teenager Ruben Neves after the highly rated midfielder was rested for a league victory over Pacos de Ferreira on Saturday.
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