Oksana Grigorieva’s legal team is in crisis after her top family law attorney suddenly quit the case before a critical deposition, Breaking Celebrity News has exclusively learned.

Mitchell Jacobs — a family law attorney who has been a Board Certified Family Law Specialist since 1986 — handed in his resignation on Sunday afternoon, citing frustration with some of the Russian musician’s other legal advisors.

It is a brutal blow to Oksana, 40, who is scheduled to be questioned in another deposition on Thursday.

Oksana has claimed her former lover, Oscar winning actor Mel Gibson, punched her in the face while she held their infant daughter Lucia.

“Oksana is flipping out that she has lost Mitchell, who she wanted and needed to call upon during what is shaping to be a very important deposition,” a source close to Oksana told Breaking Celebrity News.

Team Oksana is now without a family law specialist, while its lead attorney, Martin Garbus, is still unable to practice law in California, as Breaking Celebrity News was first to