The French side delighted their fans by finishing second in Ligue 1 last year, in the process ending an eight-year exile from Europe's premier competition.
But the hope that greeted their achievement has been extinguished by an off-season of discontent.
Following the departure of James Rodriguez to Real Madrid, Monaco's supporters were left frustrated again as Radamel Falcao joined Manchester United in a deadline-day loan switch.
As if off-field issues were not bad enough, the club have also endured a miserable start on the pitch, picking up a mere four points from five games - including three defeats - under new head coach Leonardo Jardim.
Things, therefore, do not look rosy as Monaco begin their Group C campaign with Tuesday's visit of Leverkusen.
The Germans will be hindered by the absence of centre-back Kyriakos Papadopoulos, who dislocated his shoulder in training, while Simon Rolfes and Julian Brandt have missed out recently due to ankle injuries.
Indeed, Leverkusen have made a flying start to this term under new coach Roger Schmidt, with five successive wins preceding Friday's 3-3 Bundesliga draw with Werder Bremen.
Included in that quintet of triumphs were 3-2 and 4-0 scorelines against Copenhagen in the third qualifying round.
Leverkusen have enjoyed a rich vein of goalscoring form during those games, finding the net a total of 22 times.
Stefan Kiessling has shone in racking up nine goals, although five did come in a 6-0 thumping of minnows SV Alemannia Waldalgesheim in the DFB-Pokal first round.
The German side endured a mixed Champions League last time out, picking up their biggest win in the competition when beating Shakhtar 4-0 but also slipping to their largest defeat as they were hammered 5-0 by Manchester United.
But Leverkusen did still manage to reach the second round, where they were beaten 6-1 on aggregate by Paris Saint-Germain.
