CFR Cluj will create the upset of the season if they avoid defeat against Chelsea at Stamford Bridge on Tuesday and help stop last season's beaten finalists advancing to the last 16 of the Champions League.
Chelsea have already failed to beat Cluj in the competition having drawn 0-0 in their first meeting in Group A in Romania in October.
But Cluj have lost their last three Champions League games while Chelsea recovered from their home defeat by Arsenal last weekend with an outstanding 2-0 win at Bolton Wanderers in the Premier League on Saturday.
If Chelsea beat Cluj as expected they will qualify for the last 16, but if they lose or draw and Girondins Bordeaux beat AS Roma in Rome, the French and Italian sides will advance at Chelsea's expense.
Chelsea could still lose and go through if Roma beat Bordeaux, but coach Luiz Felipe Scolari says he is not contemplating elimination.
"I don't think about going out because I believe in these players. But we need to play better than we have so far if we want to go on," he said.
"Is it unthinkable that Chelsea go out? Well, I don't think any people in the world are thinking about this, but it is possible because we have given this opportunity to other teams," Scolari added.
Chelsea, who have not lost at home for 14 Champions League matches, start as strong favourites against visitors who shocked Roma with a 2-1 win in their opening match in Rome but have failed to win again and will finish bottom of the group.
The London side will be without Frank Lampard, suspended after being sent off in the 1-1 draw at Bordeaux two weeks ago.
But even without Lampard, Chelsea should be too strong for Cluj, who are attempting to become the first Romanian club to win in England since Universitatea Craiova beat Leeds United 2-0 in the 1979-80 UEFA Cup.
Cluj will be without playmaker Eugen Trica, who is joining Anorthosis Famagusta, while Italian coach Maurizio Trombetta will also be without injured defender Tony, central defender De Sousa, midfielder Alin Minteuan and striker Didi.
Midfielder Gabriel Muresan will play in the centre of defence and Emmanuel Kone will go into Muresan's midfield berth.
Trombetta could do with his team performing well on Tuesday as just three months after taking over as coach, he is under pressure to keep his job.
Cluj president Iuliu Muresan was far from impressed with the way the team has played recently, saying: "I'm really angry as recent performances have been poor and somebody must be responsible for that."
Trombetta told reporters last week: "I know that my job is threatened but I'm thinking now only about the Chelsea match. It's crucial for me and the players."
Chelsea: 1-Petr Cech; 17-Jose Bosingwa, 33-Alex, 26-John Terry, 3-Ashley Cole; 12-Jon Obi Mikel, 21-Salomon Kalou, 13-Michael Ballack, 20-Deco; 11-Didier Drogba, 39-Nicolas Anelka
CFR Cluj: 1-Nuno Claro; 4-Cristian Panin, 20-Cadu, 6-Gabriel Muresan, 33-Alvaro Pereira; 31-Dani, 28-Emmanuel Kone; 19-Juan Culio, 8-Sixto Peralta, 7-Sebastian Dubarbier; 17-Yssouf Kone
Referee: Peter Frojfeldt (Sweden)