Celtic face their toughest test to try and qualify for the Champions League under Brendan Rodgers, according to the manager himself, as they play AEK Athens as outsiders after a 1-1 home draw in the first leg.
The Hoops play their third-round qualifier in Greece after losing to Hearts in the Scottish Premiership at the weekend, and going out would make it arguably the biggest wobble of Rodgers' time at Parkhead.
All is not well off the field for Rodgers either, with doubts about his future at the club and Dedryck Boyata's agent hitting out at them for blocking a summer transfer to the Premier League.
Throw in Steven Gerrard giving Rangers hope of bridging the gap to their fierce rivals and it's starting to get hot under the collar for Rodgers, who has a few problems to deal with in Athens on Tuesday.
Defensive headache
Norway international Kristoffer Ajer is suspended for the second leg in Athens after going through the disciplinary points threshold. Dedryck Boyata, in the midst of some controversy with his agent claiming Celtic have broken promises to the Belgium defender, has not travelled, with boss Brendan Rodgers saying he has a bad back. There is little doubt that the Parkhead rearguard will be tested by AEK to a greater extent than in the first game in Glasgow, where the visitors spent a large chunk of the game with 10 men. Jozo Simunovic will likely partner Jack Hendry and, although Rodgers could go with a back three, whoever plays will have to be at their very best.
AEK Athens v Celtic betting (Sky Bet odds)
Moussa Dembele is back
The French striker has been out since picking up another hamstring injury in the 3-0 home win over Alashkert in the first qualifying round. Rodgers admitted that having his number one striker available again was a big boost to qualification hopes. The former Swansea and Liverpool boss will not risk Dembele from the start, but will call upon him at some point during what is sure to be a tense and exciting evening.
Reaction to Tynecastle defeat
Rodgers made five changes to his side for the trip to play Hearts in the Ladbrokes Premiership on Saturday. It was all a bit of a battle and when the smoke cleared the champions had lost 1-0 to a Kyle Lafferty goal and there were question marks around the squad's strength-in-depth. Rodgers will reinstate top players such as James Forrest, Olivier Ntcham and Odsonne Edouard and they will hope to shrug off the Gorgie defeat to rescue their European hopes.
Price of failure
Celtic have reached the Champions League for the last two seasons and have raked in a reported £60million for their troubles. Losing against AEK would see the Parkhead men drop into the less lucrative Europa League and the financial gap between that and European club football's top-tier tournament might have to be bridged by selling a top star. While the prestige of playing in the Champions League is immeasurable, there is financial pressure on Celtic to get through against the Greek side.
Sit back or go for broke?
Losing the away goal in Glasgow last week meant the initiative in the tie passed to the Greek side, who will be playing only their second competitive game of the season on Tuesday night. Celtic are not a defensive team by instinct and tradition. Rodgers' side need at least one goal and it will be fascinating to see how they go about it, whether they storm out from the start or keep their powder dry until the final stages when a counter-attack might make all the difference.