The singer, who recently divorced Ritchie, launched High Court proceedings for breach of privacy and copyright after the newspaper published 11 photographs of the event on October 19.
The Mail on Sunday obtained the pictures for £5,000 after they were copied "surreptitiously" by an interior designer working at Madonna's home in Beverly Hills, Mr Justice Eady heard.
Madonna's barrister Matthew Nicklin told the judge the newspaper "makes no attempt to defend what it did" and admitted breach of privacy and copyright. This led to Mr Justice Eady entering judgement in Madonna's favour on the issue of liability.
Further proceedings to assess the damages are expected to be heard at the High Court next year.
A Mail on Sunday spokesman described the figure suggested by Madonna's lawyers as to the value of the pictures as "simply fantasy".
"Their true commercial value today is indicated by the very modest sum we and other publications paid for them."
This article was first published on brandrepublic.com