Barshiba followed up her victory in the Lancashire Oaks with a pillar-to-post success in the Plantation Stud Stakes at Newmarket.
Despite hanging her head to one side and looking a difficult ride for Jamie Spencer, she ran her rivals into the ground as she took a 7lb penalty in her stride.
She crossed the line three lengths clear in this Listed contest with Princess Taylor second and Uvinza a further three and three-quarter lengths back in third. Henry Cecil's Flame Of Gibraltar was a major disappointment.
Winning trainer David Elsworth said: "Her owner Jeff Smith decided to keep her in training and we thought it might be fun to try her over a mile and a half this season.
"I would say she's at the peak of her powers at the moment. There are two options for her now - the Nassau in two weeks' time or there's the possibility of the Yorkshire Oaks."