Her next performance was on 3 January 1811, where she played Lady Anne in "Richard III" with George Frederick Cooke in the title rôle. She followed it with Lady Rodolpha Lumbercourt to his Sir Pertinax MacSycophant in Charles Macklin's "Man of the World"; Charlotte to his Sir Archy MacSarcasm in "Love a la Mode" by the same author; and Lady Percy to his Falstaff in "Henry IV, Part 1". Other roles she played at this time were Miranda, with her husband as Marplot, in "The Busy Bodie" by Susanna Centlivre; and Eliza Ratcliff, with John Bernard as Sheva, in "The Jew" by Richard Cumberland. She also appeared in the pantomimes "Oscar and Malvina" by William Reeve, in which she also danced; and "Brazen Mask" by James Hewitt. On 29 April 1811 the Duffs appeared at a benefit in which Mary danced a solo while her husband performed in "The Three and the Deuce" by Prince Hoare. The latter was so popular that he would go on to repeat this triple-role performance more than eighty times over the course of his career. Mary's first season in Boston ended with her playing Victoria in Hannah Cowley's "A Bold Stroke for a Husband".