Colin's Sister continued her winning spree with a comprehensive success in the Weatherbys GSB Goes Online Jane Seymour Mares' Novices' Hurdle at Sandown.
Placed in a Listed bumper at this venue last spring, the Fergal O'Brien-trained six-year-old made a winning start to her career over jumps at Chepstow in October before bolting up at Warwick.
She comfortably graduated to Listed class when completing her hat-trick at Haydock and was the even-money favourite stepped up to Grade Two level in Esher.
Paddy Brennan's mount was never too far off the speed and tracked the pacesetting Happy Diva into the home straight.
Brennan looked behind for non-existent dangers on the run to the second flight from the finish and a bold leap saw her land in front.
Colin's Sister quickly put daylight between herself and her toiling rivals and while she hung under pressure on the long run-in, she still passed the post with nine lengths in hand.
Happy Diva clung on to second place from Ms Parfois.
O'Brien said: "That was very good and we were very hopeful coming here today.
"She is a racehorse and a filly and sometimes it's not always straightforward, but she is pretty straightforward and pretty special and we're lucky to have her.
"Paddy was happy with her. He gave her a squeeze going down the hill and she was on and off the bridle a bit, but she's given some nice fillies 5lb and annihilated them."
Colin's Sister could step out of novice company for a shot at the OLBG Mares' Hurdle at next month's Cheltenham Festival, with O'Brien not keen on dropping in distance for the Trull House Stud Mares' Novices' Hurdle at the showpiece fixture.
He added: "We'll get her back and speak to Paddy. Do I go for the Mares' Hurdle, or keep to novice company as we have done all season?
"The mares' novice hurdle would be too short, unless it came up very soft. My heart is saying the David Nicholson, as that's the one we all want to win, but there's some very good mares in it. The Albert Bartlett could be another option.
"It might depend on the ground. Ideally she wants it soft, but even she found it hard work today."