Speaking after the official press night at the Barbican, Ventham defied the critics to declare the 39-year-old "Sherlock" actor was "a bloody good Hamlet," reported The Guardian.
Ventham said she and Benedict's father, Timothy Carlton, both also actors, were "extraordinarily proud."
"He was quite lively growing up, but I thought that was phenomenal."
As the fastest-selling show in London theatre history, the production, directed by Lyndsey Turner, had been subject to intense scrutiny in the buildup to the press night. But after all the excitement, Ventham's glowing praise was in the minority.
Much of the criticism focused on the staging and design.