Chelsea may have spent over £500 million ($603 million) on new players, but their first season under new ownership will end without any trophies to show for it unless they can conquer Europe in the coming months.

The Blues travel to face Borussia Dortmund in the first leg of their Champions League last 16 tie on Tuesday already out of both domestic cups and languishing 10th in the Premier League.

Winning the Champions League for a third time could even by Chelsea’s best route back into the competition next season as they sit 10 points adrift of the top four in the English top flight.

Graham Potter’s men have won just two games in their last 12 since European football shut down for the winter.

Potter has had to juggle a lengthy injury list and bed in an avalanche of January signings, while also trying to maintain harmony in a bloated squad of 33 first-team players.

The former Brighton boss has already had tough choices to make for the rest of his side’s European campaign.

With only three new players allowed to be added to Chelsea’s Champions League squad and eight new signings, Benoit Badiashile, Noni Madueke, Andrey Santos and David Datro Fofana have been left out, while Malo Gusto will spend the second half of the season back on loan at Lyon.

Three 100 million euro men

But the three additions of Joao Felix, Mykhailo Mudryk and Enzo Fernandez should add firepower and a creative spark to a side badly lacking in a goal threat.

All three have commanded a 100 million euro ($107 million) fee at some point in their careers.

Fernandez’s 121 million euro move from Benfica last month broke the British transfer record just weeks after Mudryk was signed from Shakhtar Donetsk for an initial 70 million euros that could rise to 100 million.

Felix failed to live up to his 126 million euro price tag in three-and-a-half years at Atletico Madrid, but has looked lively in the early days of his loan spell at Stamford Bridge either side of a three-game ban for a red card on his Premier League debut.

The Portuguese international scored his first goal for the club from Fernandez’s fine cross in Saturday’s 1-1 draw at West Ham. But Felix’s strike was just Chelsea’s third in the last seven games.

"The second-half is probably more of a reflection of where we are as a group and as a team,” said Potter after Chelsea’s bright start at the London Stadium quickly fizzled out.

"In terms of players getting up to speed, returning from injury and players adapting to the Premier League."

Potter is aware patience is wearing thin among a fanbase that got used to a hire-and-fire culture under Roman Abramovich that reaped rewards.

In each of the two seasons Chelsea won the Champions League during the Russian’s 19-year tenure, they changed managers mid-season.

Chelsea have already done that this season as Potter replaced Thomas Tuchel in September.

A nine-game unbeaten run to start his spell in charge now seems a long time ago for Potter with the pressure ramped up to produce results, even if the bulk of Chelsea’s unprecedented level of spending has been on young players.

“You can’t talk about the long-term because that doesn’t exist in this job," added Potter.

"You have to acknowledge there’s a long-term but there’s a short-term and medium-term that is challenging for us in terms of results.

"We have to understand that, go to Dortmund with humility, with respect, and try to get the result."

Failure to do so and Chelsea's American consortium of owners may turn to another manager to deliver a return on their investment.