A study by governing body UEFA showed the COVID-19 pandemic cost European clubs seven billion euros ($7.91 billion) across two seasons even as player wages at top sides rose by 2% to 11.9 billion euros ($13.45 billion) during the period.
Top-flight clubs suffered losses worth four billion euros ($4.52 billion) in 2021, up from three billion euros ($3.39 billion) the previous year.
The majority of losses came due to empty stadiums, with revenues from ticket sales falling by 88% in 2020-21. Transfer revenues also took a tumble, dropping by 40%.
British media said the report, which included 724 clubs across 54 top divisions in Europe, added that 900 million euros ($1.02 billion) was given in rebates to broadcasters, while sponsorship revenue plummeted by 1.7 billion euros ($1.92 billion).
UEFA President Aleksander Ceferin, however, said there was reason for optimism with fans returning to stadiums.
"One lesson of the last two years has been that it is only by showing solidarity and working together that European football can overcome existential challenges such as the pandemic," he said.
"This report provides sobering details of the post-pandemic challenges that await us. But whether the pandemic stays or goes, European football will stay strong, stable and united in 2022."