The former French international, who was earning £500,000 a month while playing for the English Premier League Champions, brought his case to an employment tribunal last month.
Mendy claimed he had been assured by a senior club official he would receive his unpaid wages once he is cleared of the charges.
The 30-year-old defender, who now plays for French Ligue 2 club Lorient, was found not guilty of six counts of rape and one count of sexual assault in January 2023, but the same jury could not reach a verdict on another count of rape and one count of attempted rape.
After a retrial, Mendy was found not guilty of both charges.
Employment judge Joanne Dunlop said in a ruling she had concluded that Mendy was "entitled to recover some, but not all of the sums claimed".
She said that while Mendy was not in custody, he had been "ready and willing" to work.
In those circumstances and in the absence of "any authorisation in the contract for the employer to withhold pay he was entitled to be paid", she added.
Welcoming the ruling, Mendy said he was "delighted".
He said he hoped the "club will now do the honourable thing and pay the outstanding amounts... so I can put this difficult part of my life behind me".
Mendy spent two periods in custody, which accounted for approximately five months of the 22-month period covered by his claim, meaning the amount owed is likely to be around £8.5 million.
ALSO READ | CA squashed it quickly: David Warner on India A's ball tampering controversy, asks board to release statement
According to tribunal documents, Mendy "very quickly ran out of money" due to the non-payment of his wages, forcing him to sell his £4.8-million mansion to cover legal fees, bills, and child support payments.
The exact amount he will now receive is due to be calculated by Mendy and the club -- or by the tribunal if they are unable to reach an agreement.
The club continued paying Mendy's salary following his first arrest in November 2020.
But they argued they did not have to after he was charged because of his bail conditions and a Football Association suspension meant he was not able to perform his duties as a player.
Disclaimer: This story has been published from a news agency feed with minimal edits to adhere to web's style guide. The headline may have been changed to better reflect the content of the story or to make it more suitable for web audience.